Steel Plyometric Box Set of 12", 18", 24", 30"This American Barbell Plyo Box set provides four stackable boxes ranging from 12 to 30 inches in height. Made from durable square tubular steel construction with fully welded frames, these step up boxes provide a stable platform to support your body weight. There are no screws on these boxes, so you dont have to worry about separate pieces coming apart under pressure. The boxes feature a non slip vinyl surface to provide a secure jumping platform. The