Sram 11 Speed X-Horizon derailleurs, 12T Ceramitech Pulley Set (set of 2)Info Product Intro Vid Maintenance Vid Rock solid chain control means crisper shifts while Ceramitech bearings channel all your hard work to the ground. Each cog set features DELRIN 510GR construction, a fiber reinforced polymer specially suited to high strength situations where resistance to deflection is paramount, such as every time you shift. The Sram Ceramitech bearings are in molded for absolute security and durability as well as ease of