Place minimal pressure on your ankle and knee joints performing step aerobics exercise with Stackable Steps. Made of high-density molded plastic, these durable aerobic steps can support up to 250 lbs. Stackable Steps have rounded corners and non-slip tops that help reduce your risk of injury, and 6 rubber feet keep its base from shifting during your exercise routine. As their name suggests, these aerobic steps can also be stacked for convenient storage. Available in 4″ and 6″ heights.