This is an updated version of the Oversize Pulley Wheel System for Shimano 9100/9150 and 8000 SS/8050 SS. This new design features an integrated stop tab for easier installation. The CeramicSpeed Oversize Pulley Wheel System has been proven as the world's fastest pulley wheel system, guaranteeing an energy saving starting from 2.4 watts compared to standard Shimano systems. The OSPW system for Shimano 9100/9150 and 8000 SS/8050 SS is a state-of-the-art product in the industry, chosen by many of the world's leading professional cycling and triathlon teams. It features a 13-tooth upper pulley and a 19-tooth lower pulley for absolute rear derailleur optimization. The oversized aluminum pulleys, upper and lower, are fitted with standard or coated CeramicSpeed bearings. Note: The OSPW System for 9100/9150 and 8000 SS/8050 SS is not compatible with Ultegra 8000-GS or 8050-GS derailleurs (medium cage), nor with Ultegra RD RX800 & RX805 derailleurs equipped with a clutch. For a version compatible with RX800 & RX805, see our OSPW X for Shimano RX800/805. For a compatible upgrade for Ultegra 8000-GS or 8050-GS, see our Pulleys for Shimano, 11s NW. While there are design similarities, this OSPW is not compatible with Shimano 12-speed series 9200 or 8100 derailleurs. The Shimano 9100/8000 OSPW system is compatible up to a 32-tooth cassette for both Dura Ace and Ultegra derailleurs. In the package: Complete OSPW System for Shimano 9100/9150 and 8000 SS/8050 SS. CERAMICSPEED UFO TECH Bearing Oil. 15 ml Dropper Bottle for Pulleys.