Cycling Rear Derailleur Guide Wheel Bicycle Rear Mech Derailleur Pulley Wheel Aluminum Alloy 11TSpecifications:Material: Aluminum alloyColor: Black、Blue、Red、Gold、TitaniumNet weight: 11gType: 11TSize: Show as the picturesFeatures:Support for 7\/8\/9\/10 Speed.Shaft core diameter of 6mm、 can be used to convert units to be compatible with 4mm and 5mm screws of the guide wheel.Guide wheel selection principles: try to use the same size as original guide wheel、if not the same、 you can choose small size than the original guide、but can not use large.Package includes:1 x Bicycle Derailleur