Strengthens muscles, improves posture, balance, and core stability, helps prevent back and spine pain 55cm diameter (22") is designed for individuals from 5'1" - 5'6" tall For men or women, stretch the limits of your physical fitness by integrating stability exercise into your workout or rehab routine and develop the core muscles for fall prevention Easy to clean, comes deflated with two plugs, one inflation adaptor, and a 24 exercise guide poster, Power Pump for easy inflating sold separately Use to exercise abdominals, back, glutes, hips and other muscles, great for rehab and flexibility