The CAP Adjustable Aerobic Step Platform in Gray is a great addition to your cardio workout. The FOUR included black risers allow you to intensify your workout by adjusting the height of your aerobic step. Combine other fitness accessories (not included) to burn additional fat and calories during your cardio session. The non-slip step surface provides a safe, secure surface during your workouts. Great for high or low intensity cardio workouts. For indoor or outdoor use on a flat, dry surface. Includes 30-day limited manufacturer warranty when purchased directly from manufacturer.