CeramicSpeed OSPW X Pulley Wheel System for SRAM Eagle AXS - Alloy Pulley, Carbon Cage, BlackThe CeramicSpeed Oversized Pulley Wheel System provides optimization and increased efficiency of the rear derailleur through its extremely low friction bearings and unique overall design. Features standard hardened steel bearing races Only compatible with SRAM XX1 Eagle AXS and X01 Eagle AXS (electronic) Not designed for use with SRAM Eagle Mechanical Features a 14 tooth upper and 18 tooth lower, aluminum pulley wheels with Grade 3 Silicon Nitride