ITEM NAME:11T Aluminium Alloy Wheel Bike Rear Derailleur Pulley Guide Bearing New Hot BYD.11T Aluminium Alloy Wheel Bicycle Rear Derailleur Pulley Guide Bearing. Teeth: 11T. 1 x Wheel Rear Derailleur Pulley. Type: 11 Gear Guide Pulley. Material: Aluminum Alloy guide body + steel PEI Forest.