Shimano steps e8050 e8000 chainringthis chainring has been enhanced with shimano's dynamic chain engagement dce. This is used to hold the chain and help prevent chain jump out and 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 durabilitywith double chain guard12 speed chain compatiblechain ring fixing lock nut not includedfor 50mm chain linemanufacturer code smcre80b4dga 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.