These soft plyoboxes are designed to be less intimidating than steel boxes for the developing athlete. Standard 28" x 28" base with 5 different heights available. The 3" high box is built with 2.2 lb. density polyethylene foam, (all other sizes with 1.8 lb.) which provides stability, shock attenuation, and performance. Boxes are secured for stacking with industrial strength Velcro and have a durable vinyl cover. All boxes are less than 28 lbs. and have two reinforced handles for portability. Set of 5 includes Plyoboxes in 5 heights: 3"H, 6"H, 12"H, 18"H, & 24"H.