ENLEE 11T/13T Road Bike Rear Derailleurs Ceramic Bearing Aluminum Alloy MTB Bicycle Rear Derailleur Pulley Guide Wheel Cycling Accessories Feature: 1. Aluminum alloy high-strength shell: made of high-strength aluminum alloy and CNC to improve the durability. 2. Deepening tooth marks: it can effectively reduce the situation of chain loss, the speed change is clearer, and the upper chain is more stable. Specification: Name: ENLEE mountain road bike rear derailleur guide wheel Material: aluminum alloy body + ceramic peloton Color: red/blue/black/gold/glossy Specification: 11T/13T Size: about 41x41x9mm/1.61*1.61*0.35in, about 50.5x50.5x9mm/1.99*1.99*0.35in Net weight: about 7g/8.3g The diameter of the middle hole: 6mm/0.24in Inner diameter of two reducer sleeves: 5mm+4mm Applicable: 8/9/10/11 speed variable speed system Principles for selecting guide pulleys: 1. Give priority to the same size as the original guide pulley, without the same size, you can choose the smaller one than the original guide wheel, but not the larger one. 2. There is no difference between the guide wheel and the tension wheel, but some of the original guide wheel is different from the tension wheel, and it can also be changed to the same size, and the length of the chain needs to be re-adjusted. Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement. 

1 X Road Cycling Rear Derailleur 2 X Reducer Sleeves