It looks like you're referring to a 25 cm yoga ball, which is often used in Pilates and balance exercises for core strength and indoor training. These small exercise balls are great for improving balance, flexibility, and overall strength by engaging multiple muscle groups, especially the core.

If you're considering incorporating this into your routine, here are some exercises you can try with a 25 cm yoga ball:

1. Core Activation: Sit on the ball with your feet flat on the ground. Engage your core by pulling your navel toward your spine, and hold the position for a set amount of time.

2. Balance and Stability: Perform squats or standing exercises while balancing on the ball to enhance stability.

3. Plank Variations: Place your feet on the ball while in a plank position to challenge your balance and engage your core even more.

4. Hamstring Curls: Lie on your back with your feet resting on the ball and roll it towards you using your legs. This helps strengthen your hamstrings and lower back.

SPECIFICATIONS

• pocket description: Utility pockets
  Hign-concerned Chemical: None
  Blocking: REGULAR
  Department Name: Women

  Fit: Fits true to size, take your normal size
  Pattern Type: Solid