These chainrings are for Shimano direct mount cranks. The Wolf Tooth chainrings feature our patented Drop-Stop(R) design for the best wear life, chain retention and mud clearance. Compatibility: - Shimano XTR M9100, XT M8100, SLX M7100, and Deore M6100 series 12 speed cranksets. - Our chainring offset matches the offset of Shimano chainrings to replicate the intended chainline for the crankset. - Available in multiple tooth profiles for optimal performance based on your chain type. Use Drop-Stop ST for use with Shimano 12-speed Hyperglide+ and 12spd KMC chains. Use Drop-Stop A for all 9, 10, and 11spd chains or 12spd SRAM Eagle, KMC, Connex or Wippermann chains. Drop-Stop B is optimized for SRAM 12 spd Transmission (T-type) and Road Flattop chains but is compatible with all chains that work with Drop-Stop A. DROP-STOP A - Wolf Tooth Drop-Stop A is the original patented wide/narrow chainring compatible with multiple drivetrain brands including 9, 10, 11, and 12spd SRAM Eagle, KMC, Wippermann, etc. - NOT compatible with 12spd SRAM Transmission (T-Type) Flattop, 12spd Shimano HG+, or 12spd Campy DROP-STOP B - Compatible 9, 10, 11, and 12spd SRAM Eagle, 12spd SRAM Transmission (T-type) Flattop, 12spd Campy, 12spd KMC - Not compatible with 12spd Shimano HG+ chains DROP-STOP ST - Compatible with 12spd Shimano Hyperglide+ chain and 12spd KMC chain only - Symmetric Trapezoidal (ST) tooth shape is optimized for Shimano HG+ chain Recommendations - If you plan to ride in very muddy conditions, we recommend a chainguide or chainkeeper in addition to a clutch-type rear derailleur. Without these precautions, you may experience chaindrops and/or chainsuck. Tech Specs: - Weight: 32t/66g | 34t/72g | 38t/81g - Material: 7075-T6 aluminum - Made in the USA