Power Systems Step Up Box with Wheels, Height Adjustable from 14-20 Inches, 28 x 20 Inch Platform, Black (40210) Helps maximize leg power, quad strength and overall speed 3/4 inch plywood platform with non-skid surface and durable steel construction Base: 28 x 28 inches and Platform: 28 x 20 inches Platform adjusts to 4 different height options: 14 inch, 16 inch, 18 inch, 20 inch Attached wheels and handle for easy mobility