The MaxLiving Inflatable Wobble Cushion, also known as a stability cushion, exercise disc, balance cushion, or stability disc, is a simple, round inflatable device used to strengthen core stability and improve balance. A rocking cushion is strong enough to sit on and stand on with the benefits of an unstable surface. Use it as a fun and easy way to warm up and stretch your spine throughout the day. One side has a domed surface, the other has a ribbed surface for easy gripping.