These chainrings are for Shimano direct mount cranks. The Wolf Tooth chainrings feature our patented Drop-Stop® 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. Super boost cranksets -models M8120, M8130, M7120 and M7130 - use the Boost chainring. These Super Boost cranksets have a longer spindle and do not use the Super Boost chainring. These cranks and ring should ONLY be used on bikes with Super Boost rear hub spacing (157mm) Boost cranksets - models M9100, M8100, M7100, MT610 - will use a Boost ring with Boost rear hub spacing (148mm) and a Super Boost ring with Super Boost rear hub spacing (157mm). Use Drop-Stop ST with Shimano 12-speed Hyperglide and 12spd KMC chains. DROP-STOP TECHNOLOGY Wolf Tooth’s patented Drop-Stop® wide/narrow tooth profile delivers ultimate chain retention and mud shedding ability. RECOMMENDATIONS We recommend the use of a clutch style rear derailleur for the best chain security. For a longer lasting and more durable option, check out the CAMO System that offers stainless steel chainrings.