Wolf Tooth Direct Mount Chainrings for Shimano E-Bike Motors have a 55mm chainline and are compatible with all Boost and Super Boost bikes that use the Shimano EP8, E8000, and E7000 e-bike motor splines. Direct Mount Chainrings for Shimano E-Bike Motors are machined with 7075-T6 aluminum at Wolf Tooth in Minnesota, USA. This chainring is only suitable for Shimano 12-speed Hyperglide and 12spd KMC chains. Drop-Stop technology: On Wolf Tooth’s patented wide/narrow chainring, the wide side of the tooth has maximum contact on the drive side which spreads the load and improves chainring life. The narrow side allows clearance for mud and debris which reduces friction. Alternating wide/narrow tooth pattern prevents chain derailment. COMPATIBILITY Compatible with all Boost and Super Boost bikes that use the Shimano EP8, E8000, and E7000 e-bike motors 55mm chainline Available in two different 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. 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. 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. SPECIFICATIONS Weights: 32t • 87g | 34t • 92g Material: 7075-T6 aluminum Made in the USA The Story Wolf Tooth was founded to design and manufacture precision cycling products that emphasize function, performance, and reliability to meet the needs of our fellow racers and riders. We are a group of cyclists in Minneapolis, Minnesota that spend a lot of time talking about bike components. Like most detail-obsessed riders, we're always looking for new products that could make our bikes lighter, faster, more versatile, or more reliable. We pride ourselves on delivering premium products of the highest quality.