BKCJ – 0501 – 12/14 tooth, XD15 Ceramic Hybrid Bearing, Machined Delrin Derailleur Pulleys for 12 speed SRAM Eagle Derailleurs (5mm bolt hole) The ultimate upgrade pulley. Guaranteed to last forever against corrosion Precision machined Delrin Derailleur pulleys featuring XD15 Ceramic – Hybrid, radial bearings for enhanced shifting performance and longevity. Designed and manufactured for performance, these pulleys feature CN (tight clearance) bearings in the upper pulley to maximize shifting accuracy and C4 (loose clearance) bearings in the lower pulley to allow for chain – line movement. 500 AF Delrin pulley material features a high mechanical tensile strength and rigidity, natural lubricity, high resistance to moisture, caustic chemicals and UV makes these pulleys highly durable, rigid and very smooth. The 12 tooth upper pulley/14 tooth lower pulley set 5mm bolt – holes is designed as an upgrade for SRAM 12 speed cable – actuated Eagle derailleurs (includes XD15 cable idler pulley.) Enduro Derailleur Pulleys are available in a number of configurations and performance levels and are all are proudly precision manufactured in the USA.