The DKN 65cm (25.6) gym ball is perfect for sit-ups, back exercises & general fitness training. The ball incorporates anti burst technology that guarantees great quality & durability. The DKN gym ball is a versatile training aid designed to last & is suitable for use on any surface. The ball features the diameter of 65cm (25.6) & is made from anti-burst foam PVC. In addition, it comes with a workout video & a pump.