This freewheel was used on race bikes with or with out deraiuller.Needed to complete that old school bmx bikeSuitable for Fixed Gear Bike，Bike Tryall，single speed flywheel，removableSpecificationsInner diameter: 34 mmOuter diameter: 66 mmThickness: 16 mmColor:BrownFit: 1/8\" BMX chainGear Teeth: 16TMaterial: SteelPackage include1 x 16T Singlespeed Freewheel Sprocket