Crown Sporting Goods Set of 3 Plyometric Jump Boxes – Step Platform, Fitness Training & Conditioning Equipment for… $374.48 Make sure this fits by entering your model number. PLYOMETRIC JUMP BOXES: Take your routine to new heights. Add speed, agility, endurance, and power to your lower body 3-PACK STRENGTH SET: The Strength set gives you three sizes of jump boxes to train with (24″/30″/36″); each box stacks on top of one another for easy storage