The balance disc is an important strengthening tool that can be used by adults and children. The simple act of sitting on the disc activates core abdominal and trunk muscles. Flexor and extensor muscles work in tandem to keep your balance on the disc while continuously strengthening and toning. Through these small, continuous motions that you are making, deep core muscles are constantly stimulated and enhanced. Features - Color: Blue. - Material: PVC. - Size: Approx. 33 x 33cm/ 13 x 13 inch (LxW). - Balance disc promotes core stability, strengthens muscle tone, improves balance and body posture. - Used as a wiggle seat to provide sensory input, and to help calm children that have a hard time sitting still. - Ergonomic seating, relieves back pain and shoulder aches - Balance cushion provides an unstable surface to exercise on, requiring you to use more muscles to stay balanced. - A hand pump is included for adjustment. Stability disc size of13 inches / 33 cm diameter Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.