Plyometric platforms have become one of the most important training devices in gyms today. Great for improving explosiveness, speed and vertical jump. Proper plyometric training w/ help minimize muscle strain and injury. Platforms are constructed of 1" diameter 16 gauge steel tubing w/ powder coated finish and a .75" plywood top covered w/ heavy non skid rubber. For indoor or outdoor use. Stackable design for easy storage. 5 piece starter set consists of 2/18", 2/24" and 1/30" platform.