Adjustable Height: Increase or decrease the intensity level of your workout by adjusting the height of the Aerobic Step. The platform alone is 4A high. Adding one riser to each side creates a total height of 6A. Adding all four risers to the platform (two on either side) will create a height of 8.5A. Quality: Constructed of durable high-density polyethylene with TPE surface texture. Durable enough to withstand repetitive use. Supports up to 600 pounds.