Wolf Tooth Direct Mount Chainring - 40t, SRAM Direct Mount, For SRAM 3-Bolt, 6mm Offset, Drop-Stop B, FlattopDirect mount rings designed for use with SRAM cranks that utilize their 3 bolt mounting style. This premium 7075 T6 Aluminum Alloy chainring is equipped with the patent pending Drop Stop asymmetrical tooth design for the best in wear life, mud clearance, and chain retention. Drop Stop chainrings are designed for use with 1x9, 1x10, 1x11 and 1x12 drivetrains Compatible with all 10 , 11 , and 12 speed chains, with the exception of Shimano 12 speed