The 8 Pound Accelerator 1 Medicine Ball is very popular in the weight room when it is used for chasing exercises after major lifts. Ideal for high velocity/volume rotations sit up and throws and shoulder girdle plyometrics.All balls are 14 inches in diameter impact absorbing and moisture resistant. The casing is sewn from 18 oz. flexible vinyl coated polyester. The standard colors are black and gray but many custom color designs are available. The casing design and construction insures that the implement remains dimensionally stable and balanced. The Dynamax trade secret and craftsmanship utilize the casing to retain the various fibrous cores under tension so that each ball regardless of weight has the friendly feel and will absorb high velocity impact. Each ball carries a warranty against stitch and lacing failure.