Ideal for core strength training, stretching, toning, resistance exercises, yoga and pilates, this durable and effective Small Fitness Gym Ball makes the perfect training companion. Get into shape with this 21″ fitness gym ball featuring gripping ridges that provide excellent traction. Perfect for use at home or at the gym, this fitness ball helps you isolate specific muscle groups during training and also increases balance and coordination. Air pump needed (not included). Comes in assorted colors. Small Fitness Gym Ball,