These plyometric boxes provide maximum stability and durability with their steel construction and fully welded frames. Any athlete can use these boxes for forward jumps, lateral jumps, and other plyometric drills. Available in multiple heights for developing reaction time and overall explosiveness. Nonslip platform maximizes safety. Square tubular steel construction. Tops are reinforced 3/4" plywood with nonslip surface. Rubber bottoms protect floor. Stackable for easy storage. Use indoors or outdoors. Red/Black. Additional shipping charges will apply to the Starter Set.Starter Sets include one each of 12", 18", 24", and 30" boxes.