The york sts stackable plyometric box standard set have many uses and height options in particular you can use the plyometric boxes for explosive training and step up boxes for all over body conditioning circuit based training key features of the york sts stackable plyometric box standard set set includes 1 x 3 inches76mm stackable plyo box 1 x 6 inches152mm stackable plyo box 1 x 12 inches304mm stackable plyo box 12mm high density rubber is used to cover the top of the boxes which ge