ITEM NAME:11T MTB Rear Derailleur Jockey Wheel Ceramic Bearing Guide Roller (Red) Product Description Description: 11T Bicycle Rear Derailleur Jockey Wheel Ceramic Bearing Aluminum Alloy MTB Mountain Bike Guide Roller Specifications: Material: Aluminum alloy Color: Red Product size: 45mm*45mm*3mm/1.77*1.77*0.12" Size: Inner diameter 8.8mm/0.35", outer diameter 43.4mm/1.71", thickness about 0.6cm/0.24" Screw hole of rear gear: 8.9mm/0.35" Gland hole size: 0.5cm/0.20" Size: 11 teeth Net weight: 13g Gross weight: 13g Suitable for bearings Notes: 1. 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! 2. Please allow 1-3cm measuring deviation due to manual measurement. Included: 1 X 11T Bicycle Rear Derailleur Guide Roller.Included: 1 X 11T Bicycle Rear Derailleur Guide Roller. Gross weight: 13g. Screw hole of rear gear: 8.9mm/0.35". Net weight: 13g. Color: Red. If item is defective after 3 months, you can still send it back to us.