RaceFace ERA Direct Mount Chainring - 30t DM CINCH For Shimano 12-Speed HG+ Compatible Chain BLK52mm chainline for 148mm rear spacing Stainless steel teeth provide a 500% increase in wear durability over aluminum. Carbon fiber construction reduces ring weight while improving stiffness and power transfer Direct Mount (DM) fits 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 Shimano 12sp (SHI12) and SRAM 11 12 Shimano 11 (NW) versions TECH SPECS