These chainrings are for Shimano GRX cranks. They feature our patented Drop-Stop(R) design for the best wear life, chain retention, and mud clearance. Drop-Stop ST is specifically for the Shimano 12-speed Hyperglide+ chain, which is used by GRX 12-speed. Drop Stop-B works with all other 9, 10, 11, and 12-spd chains, including SRAM Flattop. Compatibility: - Shimano GRX cranksets including RX600 and RX810 - Drop-Stop ST is designed for Shimano 12-speed Hyperglide+ chains - Drop-Stop B tooth profile is compatible with SRAM Flattop chain - Wolf Tooth's patented Drop-Stop wide/narrow tooth profile provides the ultimate chain retention and mud-shedding ability - Use Drop-Stop B for all SRAM Eagle, SRAM Road and Transmission (T-Type) Flattop chains, 9, 10, and 11spd chains or 12spd KMC, Connex, Wippermann, Campagnolo. DROP-STOP B Compatible 9, 10, 11, and 12spd SRAM Eagle, 12spd SRAM Transmission (T-type) Flattop, 12spd Campy, 12spd KMC Not compatible with 12spd Shimano HG+ chains