The shimano hg901 dura ace 9000 xtr m9000 11 speed chain is a super narrow lightweight 11 speed hg ev asymmetrical design chain for smooth shifts and maximum durability the outer plate design has been developed to reduce the chance of chain suck and sil tec surface treatment technology ptfe plating on zinc alloy inner and outer links and rollers makes sure the chain stays running smooth and increases durability hollow pins featured throughout the chain mean maximum weight savings the inne