Our ball chair base allows you to make the most of your yoga ball, can improve your sitting posture, and helps build core muscles, exercise and stretch during your break to get rid of your fatigue and relieve stress, ergonomic ball chair is an amazing replacement for a chair at home or work.Specification:- Material: ABS ＆ PE - W x H: 53 cm (20 7/8") × 79 cm (31 1/8")Features:- Ergonomic design, improves sitting posture- Good choice for having a yoga ball at home- Easily stores under your desk- Improved flexibility, strengthen the pelvis to help birthing- Strengthen your core muscles, reduce lower back painPackage Contents:1 × Ball Chair Base FrameNote:- There may be an error of 1-3 mm due to manual measurement.- There may be chromatic aberration due to the difference between the recording lamp and the display. Please refer to the actual product.Quality Service:- When you encounter any problems with our products, please feel free to contact us, and we will try our best to solve them for you.