Shimano steps sm cre80 r chainringthis 12 speed chainring has been enhanced with shimano's dynamic chain engagement dce, which is used to hold the chain and help prevent chain jump out. This is achieved by using a broader and taller tooth profile in conjunction with a special hooked leading edge and alternate profiled tooth shaping. This provides superior chain retention, lower driving sound, increased durability and drag to a minimum.featuressteel teeth and alloy spider construction for rigidity, lightweight and durability12 speed chain compatiblefor 50mm chain linechainring fixing lock nut not includedmanufacturer's code smcre80r7la 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products.buy shimano components from chain reaction cycles, the world's largest online bike store.