Designed specifically for Shimano 12 speed HG+ chains- Elliptical shape for improved power transmission- CNC machined aluminum ring fits Race Face cranks with Cinch System- Engineered proprietary tooth profile maintains the quiet and smooth performance of the HG+ drivetrain with legendary Wolf Tooth chain retention- Prevents premature ring and chain wear that can come from non-optimized profile- Made in the USA from 7075-T6 aluminum alloy