Round chainring designed for Shimano and other 64/104BCD cranks. Size (Mass +/-1g): 64BCD: 26T (34g), 28T (40g), 30T (44g) 104BCD: 32T(33g), 34T(40g), 36T(47g), 38T (60g) Color Black, Racing Red Compatibility All cranks with 4x 104/64BCD interface. That means Shimano, Sram, Race Face, FSA, etc Material cnc machined 7075 Txxx Aluminum. Long-lasting construction Finish type II anodizing Mounting holes 4 x 104mm BCD (or 64BCD for 26/28/30T) If you have ever thought about running 1x9/10/11 and wondered how to solve chain retention, this is an answer. Its specially designed wide-narrow tooth profile keeps the chain really snug, allowing you to leave your chainkeeper in the garage. Always use a new chain with a new chainring. The most advanced, Patent Pending narrow/wide tooth profile on the Market guarantee minimum 12 months of excellent chain retention capabilities! We mean it. You can finally take your chainkeeper off of the bike. Tested by XC Silver World Champion Marek Konwa. Used by World Champion - Maja Wloszczowska! 26/28/30T - Please note this size is in 64BCD! It provides a lot better chainline that way (around 46mm) for using granny gears. That means no rubbing while riding uphill and less drivetrain wear. Chainline will be on 6th cog from smallest on 10spd cassette. 3X crankset users, please be mindful that 30T ring may touch chainstay if not enough space, so please check (print this size chart). 26/28T will fit to all cranks. 2X crankset users will accommodate 26/28/30T ring with easy. The lightest alternating tooth solution on the bicycle market ? period.