Featuring the proprietary mud clearing Drop-Stop tooth design, these rings are designed to fit any 104 BCD crankset. Made in Minneapolis, MN with exceptional chain retention in mind, these chainrings are best paired with a clutch-style rear derailleur Drop-Stop B is compatible with 10/11/SRAM 12sp chain and Flat Top/Transmission chains. Not compatible with Shimano 12 speed Fits any 104 BCD crankset Drop-Stop technology - 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 Designed to meet the requirements for E-bike use Chainring Bolts - All tooth sizes require 1x bolts that are 6mm long with exception to 30T rings which are threaded and require bolts that are 7-10mm long Drivetrains: 1x9, 1x10, 1x11 and 1x12 drivetrains If using a 9-speed drivetrain, use a 10-speed chain. It fits tighter for better chain retention Ring Position/Type: Chain Retaining Single Ring Drivetrain Speeds: 9, 10, 11, 12 Round or Oval: Round Chainring Bolt Circle Diameter: 104mm 4-bolt Material: 7075-T6 aluminum Made in the USA Weight: 56g. (34t); 60g. (36t) Color: Black