SRAM Aeroglide Ceramic Bearing Pulley Wheel Description: This is a set of SRAM Blackbox ceramic bearing rear derailleur pulleys for road bikes. Features: Upgrade to ceramic bearing pulleys Reduce friction, increase stiffness, decrease weight, and add durability Grease is optimized for low friction and maximum longevity. Comes with 10 ml syringe Specifications: Speeds: 10 & 11 Speed Material: Ceramic Balls/Stainless Steel Races Compatibility: SRAM Red, SRAM Force, and SRAM Rival Rear Derailleurs Weight: 12g each