|The Kinetic Turntable Riser Ring is an necessity for anyone riding a Rock and Roll Trainer. Features a swiveling base that allows the front wheel to move freely and helps a rider perfect their technique. With four available heights, the riser ring is designed to meet the needs of riders who want a level bike when they train or riders who want to simulate riding uphill on their trainer. Adjustable to four heights (1/2in., 1in., 1.5in., and 2in.) to fine tune your ride position and fits tires up to 2.25 inches. PVC construction for a lifetime of use.