STURDY CONSTRUCTION. The Body Sport Aerobic Step is made of tough, textured rubber that provides a non-slip surface and sturdy construction, offering users the stability and support they need for their workout ADJUSTABILITY. The 39 in. x 15 in. Body Sport Aerobic Step allows users to adjust the height of the platform to 6 in., 8 in., and 10 in. heights for varying levels of difficulty CARDIO & REHAB. The Body Sport Aerobic Step is perfect for cardio training and lower limb rehabilitation exercises and workouts CONVENIENCE. The Body Sport Aerobic Step is lightweight and compact, making it easy to store and use for added convenience WEIGHT CAPACITY. Our Body Sport Aerobic Step Platform has a tested static weight limit of 550 lbs and a dynamic weight of 220 lbs.