The Oversized Pulley Wheel System for Shimano Dura Ace 9200 and Ultegra 8100 with integrated stop tower for simple installation and durability. The CeramicSpeed Oversized Pulley Wheels System has been proven to be the fastest pulley system in the world. CeramicSpeed OSPW Systems are an industry leading product, chosen by World Champions and top athletes around the world. This OSPW System has handbuilt CeramicSpeed Bearings installed in each pulley and comes with a 4 year warranty as standard and a lifetime warranty when choosing coated or SLT bearings. Featuring a 13-tooth upper pulley wheel and a 19-tooth lower pulley wheel to provide absolute optimisation of the rear derailleur. The upper and lower oversized aluminium pulley wheels come fitted with either standard or coated CeramicSpeed Bearings.