RaceFace Direct Mount Wide Chainring - 34t DM CINCH For Shimano 12-Speed HG+ Compatible Chain BLKShimano 12 speed specific, wide version for 55mm chainline Provides the optimal chainline and clearance for your Super Boost 157mm hubs when used with the standard Race Face 136mm spindle Also offers an extra 3mm of chainline when used with Boost 148mm hubs 7075 T6 aluminum direct mount ring to fit Race Face Cinch system splined cranks Narrow wide teeth prevent chain drop, updated tooth profile runs quieter Installs with a common Park Tool BBT 22