This is an updated version of the 3D printed Ti OSPW for Shimano 9100/8000. This new design features an integrated stop tab for easier installation. The CeramicSpeed Oversized Pulley Wheel System has been proven to be the world's fastest pulley system, guaranteeing an energy savings of at least 2.4 watts over standard Shimano systems. The OSPW System for Shimano 9100/8000 is an industry-leading product, chosen by many of the world's top professional cycling and triathlon teams. It features a 13-tooth upper pulley and a 19-tooth lower pulley to ensure absolute rear derailleur optimization. The oversized aluminum upper and lower pulleys are equipped with coated CeramicSpeed bearings. Note: The 9100/8000 system is not compatible with Ultegra 8000-GS or 8050-GS (medium cage) derailleurs, or with Ultegra RD RX800 & RX805 derailleurs equipped with a clutch. Please refer to our Shimano 11 Speed Pulleys for a compatible upgrade. While there are design similarities, this OSPW is not compatible with Shimano 12-speed 9200 or 8100 series derailleurs. In the box: Complete 13-tooth/19-tooth 3D printed OSPW System. CeramicSpeed UFO TECH Bearing Oil. 15 ml dropper bottle for pulleys.