Rear derailleur jockey wheels (pulleys) vary based on the drivetrain manufacturer and the intended use (road, gravel, or MTB).All Enduro jockey wheels are equipped with XD15 ceramic-hybrid bearings and include a limited lifetime warranty. We offer the following models: Shimano MTB 11 & 12-speed; Shimano Road 11-speed; Shimano Gravel 11-speed.SRAM MTB 11 & 12-speed; SRAM Road 11 & 12-speed; SRAM Gravel 11 & 12-speed.Plus a few additional configurations.