CeramicSpeed Oversized Pulley Wheel System for SRAM 1 x 11 Type 3 Derailleurs - Coated Bearings, Alloy Pulley, Carbon Cage, BlackThe CeramicSpeed Oversized Pulley Wheel System provides optimization and increased efficiency of the rear derailleur through its extremely low friction bearings and unique overall design. Features a 14 tooth upper pulley wheel and a 18 tooth lower pulley wheel Aluminum pulley wheels have a narrow wide profile that ensures chain retention The robust cage is crafted from polyamide and carbon fiber for durability and light weight The cage design allows