The Jockey Wheels XD15 Ceramic - SRAM Eagle 12sp by Enduro Bearings are the ultimate upgrade pulleys for your SRAM Eagle 12-speed derailleur. Made from machined Delrin material, these pulleys feature XD-15 Ceramic-Hybrid, radial bearings for enhanced shifting performance and longevity. The upper pulley has CN bearings for maximum shifting accuracy, while the lower pulley has C4 bearings to allow for chain-line movement.The pulley material, 500 AF Delrin, is known for its high tensile strength, rigidity, and resistance to moisture, chemicals, and UV. It also has natural lubricity, reducing friction when it interacts with the bicycle chain. Compared to other materials like aluminium or titanium, the Delrin pulleys offer significantly less drag.These pulleys come with Enduro Bearings' exclusive XD-15 Ceramic-Hybrid bearings. These bearings combine corrosion-proof, cryogenically treated nitrogen steel races with Grade 3 Silicon Nitride ceramic balls. The deep-groove design raceways allow for maximum-sized ceramic balls, improving performance and longevity. The pulleys are lubricated with Kluber NBU52 grease, which sticks to the balls and provides long-lasting smoothness.Designed as an upgrade for most 11-speed Campagnolo derailleurs, these pulleys have an 11 tooth size and profile with 5mm bolt-holes. Enduro Bearings offers different configurations and performance levels, including Ceramic-Hybrid and Black-Oxide treated Zero Ceramic options. All pulleys are proudly manufactured in the USA.These jockey wheels are compatible with SRAM Eagle 12-speed derailleurs and feature XD15 Ceramic bearings. The Enduro Part Number for these pulleys is BKCJ-0501.