Get the ball rolling and achieve easy, convenient core strength and stability exercise – and it’s fun too! The Body Power anti-burst gym ball provides a simple, but effective way to focus on your core strength and stability. Acclaimed by physical therapists for years, gym ball exercises help strengthen the abs and back whilst improving balance. The durable, anti-burst construction makes the ball easy to use and clean. You can feel safe and secure during every exercise. The balls should be inflated to size not pressure. To get a more accurate inflation of the ball. It is best to have a measuring tape handy. The Grey 55cm ball is designed for height 5’ – 5’6” (152.4cm – 167.64cm) and should be inflated to 21” (53.34cm). Pump included.