Women's

BIKINI

Line-up: 4 Quarter Turns (Front, Right Side, Back, Left Side).

Posing Bikini: Two-piece bikini; no G-strings allowed. The color of the bikini and the height of the high heels are free of choice.

JUDGING CRITERIA
Overall Appearance: Judges evaluate posture and poise during the stage walk. Gait, elegance, gestures, personality, charisma, stage presence, and charm, as well as naturalness, are essential factors in determining the athletes' rankings.
Proportions: The focus is on a classic feminine physique, good posture, and correct anatomical structure.
Priority: Vertical proportions (relation between legs and upper body) and horizontal proportions (relation between hips, waist, and shoulder line) are the primary judging criteria.
Muscle Mass: The physique should be neither excessively muscular nor excessively lean. There should be a subtle degree of muscle separation, but it must remain soft and feminine.
Presentation: Athletes must display a healthy, well-conditioned appearance and present themselves in an attractive and confident manner.

Classes:
Bikini (Open Category).
Bikini Masters 35+ (Athletes from the age of 35).



BIKINI SHAPE

Line-up: 4 Quarter Turns (Front, Right Side, Back, Left Side).

Posing Bikini: Two-piece bikini; no G-strings allowed. The color of the bikini and the height of the high heels are free of choice.

JUDGING CRITERIA
Aesthetics: Focus on a feminine appearance and balanced proportions.
Key Muscle Groups: Dominant shoulders, glutes, and abdominals.
Physical Conditioning:
Tone: A fit, toned physique is required, but extreme definition, prominent vascularity (veins), and visible muscle striations (ripped fibers) are not necessary.

Important Note: Competitors displaying extreme definition in the glutes or triceps will be down-graded in the rankings.

Classes:
Bikini Shape: (Open category).
Bikini Shape Masters 35+ (Athletes from the age of 35).


BIKINI WELLNESS

"T-walk" / "Stage walk" performance followed by 4 Quarter Turns.

Posing Bikini: Two-piece bikini. The color of the bikini and the height of the high heels are free of choice.

JUDGING CRITERIA
Primary Focus: Dominant legs and glutes are the defining characteristics of this category.
Upper Body: The shoulders and upper body may be more developed and muscular than in the Bikini Shape category.

Presentation:
Stage Presence: A critical scoring factor. Judges evaluate the overall stage image, charisma, and the quality of movement/posing.

Physical Conditioning:
Tone: Muscle development should be significant but without extreme definition or prominent vascularity (veins).

General Rules:
No Weight Limit: Athletes are not restricted by weight-to-height ratios.

Classes: 
1 Open Category (no height divisions).



MS. FIGURE

Line-up: Front and Back views.
Comparisons: 5 Mandatory Poses (performed with open palms to maintain femininity).
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds.

Posing Bikini: Two-piece bikini; no G-strings allowed. The color of the bikini and the height of the high heels are free of choice. Routine Note: The free routine is performed without high heels. Costumes or additional props/accessories are strictly prohibited.

JUDGING CRITERIA
Aesthetics: Focus on overall proportions, symmetrical muscle development, and femininity.
V-Taper: A balanced shoulder-to-waist ratio is a key component.

Physical Conditioning:
Muscularity: While a higher degree of muscle development is expected compared to Bikini categories, maximum muscle definition is not the primary scoring criterion. The look should be athletic and toned, but not overly "shredded" or vascular.

Classes:
Ms. Figure (Open Category).
Ms. Figure Masters 40  (Athletes from the age of 40).


MISS PHYSIQUE

Line-up: Front and Back views.
Comparisons: 7 Mandatory Poses (performed with closed fists, classic bodybuilding style).
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds.

Posing Bikini: Two-piece bikini; no G-strings allowed. The color of the bikini and the height of the high heels are free of choice. Footwear: Athletes compete barefoot (no high heels). Routine Note: No additional costumes, props, or accessories are permitted during the free routine.

JUDGING CRITERIA
Symmetry & Proportions: Evaluation of the shoulder-to-waist ratio and overall structural balance.
Muscle Mass: A well-developed, balanced muscle mass is required across all muscle groups.
Maximum Definition: Unlike the Figure category, maximum muscle definition and clear separation are essential scoring criteria here.
Stage Presentation: Confidence, posing execution, and professional stage presence.

Classes:
1 Open Category: No height or age divisions.


Men's

MEN’S PHYSIQUE

Board Shorts: Length must reach down to the knees. No sponsor logos are permitted on the shorts.

Line-up: 4 Quarter Turns (Front, Right Side, Back, Left Side).

JUDGING CRITERIA
Proportions: Focus on the "V-taper" (shoulder-to-waist ratio).
Symmetry & Definition: Balanced muscle development and clear muscle definition are essential.
Stage Presentation: Confidence, poise, and a relaxed yet athletic appearance are key scoring factors.

Maximum Weight Limit:
The maximum allowable weight is calculated using the following formula:

  • (Height/cm - 100) + 2kg

Classes:
Open Category: If more than 15 athletes register, the category will be split into two height classes.
Masters 40+: For veterans (available if a minimum of 6 participants register).

MEN’S CLASSIC PHYSIQUE

Posing Trunks: Solid color (unicolor). No sponsor logos are permitted.
Dimensions: Side seam width must be between 10 cm and 12 cm. No sponsor logos are permitted.

Line-up: Front and Back views.
Comparisons: 6 Mandatory Poses. (Note: The "Most Muscular" pose is strictly prohibited in this category).
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds. No costumes or props allowed.

JUDGING CRITERIA
Aesthetics: Focus on symmetry and classic proportions.
V-Taper: Significant emphasis on the shoulder-to-waist ratio.
Conditioning: High muscle definition and clear separation are required, while maintaining an aesthetic "Golden Era" silhouette.

Maximum Weight Limits:
Weight is strictly regulated based on height according to the following formulas:

  • Up to 170 cm: (Height - 100) + 4kg
  • Up to 179 cm: (Height - 100) + 6kg
  • Up to 189 cm: (Height - 100) + 8kg
  • Over 190 cm: (Height - 100) + 10kg
Classes:
Class II: ≤ 175 cm
Class I: > 175 cm
Masters 40+ For athletes 40 years of age and older.

MASTERS

Posing Trunks: Solid color (unicolor). No sponsor logos are permitted.

Line-up: Front and Back views.
Comparisons: 8 Mandatory Poses (Standard Bodybuilding set including "Most Muscular").
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds. No costumes or props allowed.

Classes:
Class 1: Masters 40+ (Over 40 years of age).
Class 2: Masters 50+ (Over 50 years of age).
Class 3: Masters 60+ (Over 60 years of age).
Class 4: Masters 70+ (Optional category, depending on the number of participants).

Eligibility: An athlete is eligible to compete in the Masters category starting from the calendar year in which they reach the age of 40, 50, 60, or 70.

JUNIORS

Posing Trunks: Solid color (unicolor). No sponsor logos are permitted. 

Line-up: Front and Back views.
Comparisons: 8 Mandatory Poses (Standard Bodybuilding set).
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds. No costumes or props allowed.

An athlete may compete in the Juniors category up to and including the calendar year in which they turn 23 years old.

Important: Eligibility for the Juniors category officially ends on the day the athlete reaches their 23rd birthday.

MEN’S BODYBUILDING

Posing Trunks: Solid color (unicolor). No sponsor logos are permitted.

Line-up: Front and Back views.
Comparisons: 8 Mandatory Poses.
Free Routine (Optional): A choreographed presentation with a maximum duration of 60 seconds.

JUDGING CRITERIA

Muscle Mass: Focus on maximum muscle volume and density.
Conditioning: Exceptional muscle definition and clear separation.
Aesthetics: Symmetry, proportions (shoulder-to-waist ratio), and overall stage presentation.

Weight Limits: There are no weight restrictions in this category.

Height Classes:

  • Class 4: Up to and including 165 cm.
  • Class 3: Up to and including 172 cm.
  • Class 2: Up to and including 179 cm.
  • Class 1: 180 cm and over.

MIXED PAIRS

This category features one male and one female athlete performing together as a single team.

Round 1 – Comparison Round (50% of the Total Score):
Line-up: Front and Back views.
5 Mandatory Pair Poses: Synchronized presentation of mandatory bodybuilding/figure poses.

Round 2 – Free Routine (50% of the Total Score):
Choreography: A joint routine performed to music with a maximum duration of 60 seconds.

Women: Posing bikini.
Men: Posing trunks.
Footwear: Both athletes perform barefoot (no shoes).
Restrictions: Additional costumes, props, or accessories are strictly prohibited.

JUDGING CRITERIA
Team Image: Overall appearance and chemistry as a duo.
Harmony & Synchronization: The ability to move and pose in perfect unison.
Aesthetics: Balanced body lines and visual flow between partners.
Physical Compatibility: Consistency in conditioning and muscle development between both partners.

Classes:
1 Open Category: No height or age divisions.

REGULATIONS FOR JUDGES AND ATHLETES

BIKINI

STAGE WALK The competition in this category begins with an individual stage walk. This is a short presentation designed to showcase charisma, fluid movement, and self-confidence before joining the line-up. 

  • Athletes enter one by one to the center of the stage.
  • First Stance: Face the judges, turn right (side profile), turn to the back (facing away from judges), turn right (side profile), and return to the front.
  • Back View Requirements: Legs must be shoulder-width apart, hair must be moved so as not to cover the back, and hands are kept at the sides.
  • Front View Requirements: Legs approximately shoulder-width apart, hands at the sides.
  • After the walk, the athlete moves to the back of the stage to the position indicated by the stage marshal.

LINE-UP ROUND (4 QUARTER TURNS)

  • Front Pose: One hand is placed on the hip, the other arm hangs naturally. Head is kept straight. One leg stands straight while the other is placed slightly to the side and forward.
  • Back Pose: Legs are placed at shoulder width or slightly wider and must be fully extended (knees straight). The pelvis is tilted slightly back. Shoulders are kept square and slightly flared to show a "V-taper." Hands are held loosely at the sides or slightly away from the body with palms toward the thighs.
  • Side Pose: One leg must be fully extended, while the other may be slightly bent at the knee and placed behind the lead leg. The upper body (shoulders) is slightly twisted toward the judges, while the hips remain in a side profile. Chest is up, shoulders back, and both arms hang naturally along the thighs.

COMPETITION ATTIRE

  • Bikini: Two-piece posing bikini (no G-strings allowed), color and high-heel height are free of choice. 
  • Aesthetics: Emphasis on a feminine appearance and balanced proportions; dominant shoulders, glutes, and abdominals.
  • Conditioning: Extreme muscle definition, prominent vascularity (veins), and muscle striations are not required.
  • Warning: Competitors displaying extreme definition in the glutes or triceps will be down-graded in the rankings.

JUDGING CRITERIA

Detailed Evaluation:

  • Overall Appearance: Judges assess posture during movement. Gait, elegance, gestures, personality, charisma, stage presence, and naturalness are critical for ranking.

  • Proportions: Classic feminine physique, good posture, and correct anatomical structure.

  • Priority: Vertical proportions (legs vs. upper body) and horizontal proportions (hips vs. waist/shoulders) are the primary criteria.
  • Muscle Mass: The physique should be neither excessively muscular nor too lean. A slight degree of muscle separation (separation) is required.
  • Presentation: Athletes must display a healthy, well-conditioned look and present themselves attractively.

CLASSES

  • Bikini: Open Category.
  • Bikini Masters 35+: For athletes 35 years of age and older.
Miss Bikini introduction
Miss Bikini posing

Miss Shape posing

BIKINI SHAPE 

STAGE WALK The competition in this category begins with an individual stage walk. This is a short presentation designed to showcase charisma, fluid movement, and self-confidence before the athlete takes their place in the general line-up.

LINE-UP ROUND (4 QUARTER TURNS)

  • Relaxed Stance: All muscles must maintain tone. The abdominals must be controlled, and the shoulders kept straight. Legs should be straight, and the head held straight, facing the judges.
  • Front Pose: One hand is placed on the hip, while the other arm hangs naturally alongside the body. The head is held straight. One leg stands straight while the other is placed slightly to the side and slightly forward.
  • Back Pose: Legs are placed at shoulder-width or slightly wider and must be fully extended (knees straight). The pelvis is tilted slightly back. Shoulders are kept straight and slightly flared to the sides to display a "V-taper." Hands are held loosely at the sides or slightly away from the body, with palms toward the thighs.
  • Side Pose: One leg must be fully extended, while the other may be slightly bent at the knee and placed behind the lead leg. The upper body (shoulders) is slightly rotated toward the judges, while the hips remain in a side profile. The chest is lifted, shoulders are back, and both arms hang naturally along the thighs.

COMPETITION ATTIRE

  • Posing Bikini: Two-piece; no G-strings allowed, color and high-heel height are free of choice.
  • Emphasis is on a feminine appearance, balanced proportions; dominant shoulders, glutes and abdominal press.

JUDGING CRITERIA

Physical & Aesthetic Focus:

  • Appearance: A feminine and attractive overall image.
  • Proportions: A well-balanced physique, emphasizing the shoulder-to-waist ratio ("V-taper").
  • Priority Muscle Groups: Dominance should be seen in the shoulders, glutes, and abdominals.
  • Muscle Mass: High muscle mass and extreme definition (shredded look) are not desired.

Conditioning Warnings:

  • Tone: A fit appearance is required, but extreme vascularity (veins) and muscle striations (fiber visibility) are not necessary.
  • Downgrading: Participants displaying extreme definition in the glutes or triceps will be down-graded in the rankings.

Presentation:

  • Stage Presence: The athlete's charisma, stage posture, and self-confidence have a direct impact on the final score.

CLASSES

  • Bikini Shape: Open Category.
  • Bikini Shape Masters 35+: For athletes 35 years of age and older.

BIKINI WELLNESS 

GENERAL RULES

  • Weight Limit: NONE.
  • Competition Attire: Posing bikini; color and high-heel height are free of choice.

STAGE WALK The competition in this category begins with an individual stage walk. This is a short presentation designed to showcase charisma, fluid movement, and self-confidence before the athlete takes their place in the general line-up.

LINE-UP ROUND (POSING GUIDE)

  • Relaxed Stance: One hand is placed on the hip, while the other arm hangs naturally. The head is held straight. One leg stands straight while the other is slightly bent. The upper body is minimally rotated to make the waist appear as narrow as possible.
  • Front Pose: One hand on the hip, the other hanging naturally. Abdominals must be pulled in and tight. In the Wellness category, the feet may be positioned slightly wider to emphasize the sweep of the quadriceps.
  • Back Pose (Version I): Legs are positioned at shoulder-width, slightly bent at the knees. Feet are turned slightly outward. The pelvis is tilted back (arching the lower back) to showcase maximum glute volume. Shoulders are kept narrow, and hands may be placed on the front of the quads.
  • Back Pose (Version II): One leg acts as a straight support, while the other is slightly moved to the side or half a foot back, resting on the toes. This helps highlight the transition between the glute and the hamstring. One hand is placed on the hip, the other hangs freely along the hip.
  • Side Pose: The leg closer to the judges is fully straight. The farther leg is slightly bent at the knee and placed behind the front leg, resting on the toes. This visually "lifts" the glute and showcases thigh width from the side. Hips are turned to the side, but the chest and shoulders are rotated at a 45-degree angle toward the judges. The farther arm is on the hip, while the closer arm hangs freely, ensuring it does not obstruct the glute line.

JUDGING CRITERIA

  • Primary Focus: The legs and glutes must be the dominant muscle groups when evaluating the physique.
  • Proportions: The shoulder girdle and upper body may be slightly more muscular than in the "Bikini Shape" category.
  • Symmetry and Definition: Extreme muscle definition or prominent vascularity (veins) is not an advantage. Scoring will be reduced for an overly "dried out" or depleted look.
  • Presentation: Overall stage image and performance (charisma, movement) are significant scoring factors.

CLASSES

  • Bikini Wellness: Open Class (no height divisions).

MS. FIGURE 

GENERAL RULES

  • Weight Limit: NONE.
  • Competition Attire: Two-piece posing bikini (no G-strings allowed).
  • Style: Color and high-heel height are free of choice.

JUDGING ROUNDS

1. Line-Up Round:
Consists of 2 stances: Front View and Back View.

2. Comparison Round (5 Mandatory Poses): Athletes are compared side-by-side using the following poses (typically performed with open palms to maintain a feminine aesthetic):

  1. Front Double Biceps
  2. Side Chest
  3. Back Double Biceps
  4. Side Triceps
  5. Abdominals and Thighs (front)
3. Free Routine (Optional):
A choreographed performance to music, lasting up to 60 seconds.

JUDGING CRITERIA

  • Proportions: Focus on the "V-taper" (the ratio between wide shoulders and a narrow waist).
  • Symmetry and Definition: Balanced muscle development across the entire body. Maximum muscle definition is not the primary criteria. The priority is aesthetic and harmonious muscularity. The physique must be athletic but not "overdone" or overly shredded.
  • Presentation: Correct execution of poses during the line-up and comparisons, as well as overall femininity. Judges evaluate the quality of posing, self-confidence, and feminine elegance.

CLASSES

  • Ms. Figure: Open Class.

MISS PHYSIQUE 

GENERAL RULES

Weight Limit: NONE.
Competition Attire: Two-piece posing bikini (no G-strings allowed).
Color: Choice of color is free.
Footwear: Athletes compete barefoot (no high heels).

JUDGING ROUNDS

1. Line-Up Round:
Consists of 2 stances: Front View and Back View.

2. Comparison Round (7 Mandatory Poses): Athletes are compared side-by-side using the following poses (performed with closed fists, classic bodybuilding style):

  1. Front Double Biceps
  2. Front Lat Spread
  3. Side Chest
  4. Back Double Biceps
  5. Back Lat Spread
  6. Side Triceps
  7. Abdominals and Thighs (front)
3. Free Routine (Optional):
A choreographed performance to music, lasting up to 60 seconds.

JUDGING CRITERIA

  • Symmetry and Proportions: Evaluation of the balance between the upper and lower body, as well as the shoulder-to-waist ratio.
  • Maximum Definition: Unlike other female categories, maximum muscle definition is required here. Judges look for clear muscle separation and a "shredded" appearance.
  • Muscle Mass: Assessment of balanced and significant muscle development throughout the entire physique.
  • Presentation: The ability to professionally showcase the musculature, maintain control during poses, and uphold strong stage presence.

CLASSES

  • Miss Physique: Open Class (no height divisions).

MEN’S PHYSIQUE 

GENERAL RULES

Weight Limit: (Height/cm - 100) + 2kg
Competition Attire: Board shorts (beach style). Length typically reaches the knees.
Logos: No sponsor or brand logos are permitted on the shorts.

LINE-UP ROUND (4 QUARTER TURNS)

  • Front Pose: One hand is placed on the hip, with one leg slightly moved to the side. The stance should look relaxed yet athletic.
  • Side Pose (Left/Right): Demonstrates the side profile, focusing on the thinness of the waist and the development of the obliques and shoulders.
  • Back Pose: Showcases the width of the back (V-taper) and the line of the shoulders. The lats should be spread, but not in a bodybuilding style.

JUDGING CRITERIA

  • Proportions: The primary focus is on the "V-taper" silhouette (wide shoulders coupled with a narrow waist).
  • Symmetry and Definition: Judges look for balanced muscle development and clear muscle separation (definition). Excessive muscle mass, such as that seen in Bodybuilding, is not required.
  • Presentation: The athlete’s overall image is crucial. Charisma, self-confidence, stage presence, and facial expressions are all factored into the final score.

CLASSES

  • Open Class: If more than 15 participants register, the category will be split into two height-based classes.

MEN’S CLASSIC PHYSIQUE 

GENERAL RULES

Weight Limits: Strictly regulated by height:
≤ 170 cm: (ūgis−100)+4 kg
≤ 179 cm: (ūgis−100)+6 kg
≤ 189 cm: (ūgis−100)+8 kg
> 190 cm: (ūgis−100)+10 kg

  • Competition Attire: Solid color (unicolor) posing trunks. The side seam width must be between 10 cm and 12 cm. No sponsor logos are permitted.

JUDGING ROUNDS

1. Line-Up Round:
Consists of 2 stances: Front View and Back View.

2. Comparison Round (6 Mandatory Poses):

  1. Front Double Biceps
  2. Front Lat Spread
  3. Back Double Biceps
  4. Side Chest
  5. Abdominals and Thighs
  6. Free Choice Classic Pose (e.g., Vacuum pose or favorite "Golden Era" pose)
  • Prohibited Pose: The "Most Muscular" pose is strictly forbidden in this category.
3. Free Routine (Optional):
A choreographed performance to music, lasting up to 60 seconds.

JUDGING CRITERIA

  • Symmetry and Proportions: Focus on the "V-taper" (shoulder-to-waist ratio) and harmonious muscle development. The goal is to recreate the aesthetic "Golden Era" of bodybuilding.
  • Muscle Definition: While maximum definition is a key criterion, it must not compromise the overall aesthetic appeal. The physique should look athletic and streamlined, not blocky.
  • Presentation: The ability to showcase the body with elegance, fluid transitions, and classic artistic style.

CLASSES

  • Class II: ≤ 175 cm,  
  • Class I: > 175 cm,
  • Masters 40+: For veterans aged 40 and older.

MEN’S BODYBUILDING 

GENERAL RULES

  • Weight Limit: NONE.
  • Competition Attire: Solid color (unicolor) posing trunks. No sponsor logos are permitted.
  • Cross-over Eligibility: Athletes may compete in two classes (e.g., their specific height category and a Masters category), provided they meet the age and eligibility requirements for both.

JUDGING ROUNDS

1. Line-Up Round:
Consists of 2 stances: Front View and Back View.

2. Comparison Round (8 Mandatory Poses):

  1. Front Double Biceps
  2. Front Lat Spread
  3. Side Chest
  4. Side Triceps
  5. Back Double Biceps
  6. Back Lat Spread
  7. Abdominals and Thighs
  8. "Most Muscular"
3. Free Routine (Optional): A choreographed performance to music, lasting up to 60 seconds.

JUDGING CRITERIA

  • Symmetry and Proportions: Evaluation of the shoulder-to-waist ratio and a harmonious balance between all muscle groups across the entire body.
  • Maximum Muscle Mass: Assessment of overall muscle size, volume, and density.
  • Muscle Definition: Focus on clear muscle separation and deep muscular detail.
  • Presentation: The quality of posing execution and professional stage presence.

CATEGORIES & CLASSES

Age-Based Categories:

  • Juniors: Athletes are eligible up to and including the entire calendar year in which they turn 23.
  • Masters 40+: Starting from the calendar year the athlete turns 40.
  • Masters 50+: Starting from the calendar year the athlete turns 50.
  • Masters 60+: Starting from the calendar year the athlete turns 60.
  • Masters 70+: Optional class (determined by the number of participants).

Height-Based Classes:

  • Men 4: Up to and including 165 cm.
  • Men 3: Up to and including 172 cm.
  • Men 2: Up to and including 179 cm.
  • Men 1: 180 cm and over.

MIXED PAIRS 

In this category, one male and one female athlete perform together as a single team. Judging focuses not only on individual physical preparation but also on the ability to perform as a cohesive unit.

GENERAL RULES

Competition Attire: 

  • Women: Posing bikini.

  • Men: Posing trunks.

  • Footwear: Both athletes must perform barefoot (no shoes).

  • Restrictions: Additional costumes, props, or accessories are strictly prohibited.

JUDGING ROUNDS

1. Line-Up Round:
Consists of 2 stances: Front View and Back View.

2. Comparison Round (50% of Final Score): Athletes are judged on 7 Mandatory Poses performed in unison:

  1. Front Double Biceps
  2. Front Lat Spread
  3. Side Chest
  4. Side Triceps
  5. Back Double Biceps
  6. Back Lat Spread
  7. Abdominals and Thighs (front)
3. Free Routine (50% of Final Score):
A joint, synchronized choreographed performance to music, lasting up to 60 seconds.
Tie-Breaking Rule: In the event of a total score tie, the athlete/pair with the higher Free Routine score takes the higher placing.

JUDGING CRITERIA

  • Team Image: The overall appearance, chemistry, and visual harmony of the pair on stage.
  • Harmony and Synchronization: How well the partners coordinate their movements, transitions, and posing timing.
  • Aesthetics and Body Lines: The visual balance and aesthetic flow between the two physiques.
  • Physical Conditioning: The athletic form, conditioning level, and stage presence of both partners.
  • Individual Quality: The muscle quality, development, and proportions of each individual partner as they contribute to the pair.

CLASSES

  • 1  Open Category (no height or age divisions).