Dramitcally reduce drivetrain friction with this premium ceramic bearing pulley upgrade for Shimano 12-speed road systems. Handbuilt bearings, designed and manufactured in Denmark. Two sets of pulley spacers are included, providing compatibility with Shimano Dura Ace 9250, Ultegra 8150, and 105 7150 rear derailleurs. Compatibility: Shimano 12 Speed Pulley Material: Aluminium Pulley Size:11-tooth upper & lower In the box: Two 11-tooth pulley wheels Alloy Spacer Kit CeramicSpeed Oil for Pulley Wheel Bearings, 15ml. bottle Sticker Sheet The Story CeramicSpeed is one of the world’s leading suppliers of ceramic bearings. The company consists of two specialised sales channels, focusing on cycling and industrial applications. We have more than 15 years of experience in bearings applications, and we have developed close relationships with our component suppliers over the time – each of whom is the very best in their fields. The CeramicSpeed Sports channel delivers both bearings as well as ultrafast racing chains, reinforcing the company’s goal of saving watts and delivering the lowest friction available. All our bearings are handmade and our chains are optimised by hand in Denmark.