J/fit Plyo Boxes - Plyometric Platform and Jumping Agility Box for Training & CrossFit & Conditioning ( 12", 18", 24", 30" or ALL 4 Sizes in Complete Set!) Solid steel construction frame, solid rubber non-slip mat, non-slip pads on all 4 corners Excellent tool for plyometric drills, lateral jumps and forward jumps; Develops overall explosiveness needed to develop proficiency in most sports Tapered design allows for greater stability and ease in jumping, Easy stacking for storage Rubber stoppers on the bottom are screwed into place for optimum safety and traction to keep boxes from sliding Offered in 12", 18", 24", 30"