The BSTPBS2 Body Solid 12" to 30" Plyo box set includes 4 plyometric boxes from 12 inches to 30 inches high in height increments of 6 inches. Plyometric training plays a major role in the Crossfit training as well as sport training. With the plyo box set you can increase the height of your box jumps gradually as you build more power. Multiple jump boxes can be set up in a row to progressively jump higher. The 12" to 30" plyo box set also works well in the gym setting for training multiple students at a time.