The shape conforms to most of the mountain bike,to provide effective protection for rear derailleur. prevent the derailleur was struck distortion or displacement in riding to ensure the safety of the riding.Can also be used protect rear derailleur when tripped,is very reliable. Left and right wings slot,can be more fastness install on the frame.Single fixed hole can be easily installed. The shape conforms to most of the mountain bike,to provide effective protection for rear derailleur.Protector uses Iron material and arch angle suppress,make the protector is not easy to deformation under the strong impact force,effective protect the rear derailleur.Universal size suitable for most MTB bikes,road bikes,folding bicycle.Install Method:Quick release: Just installed directly on the quick release.Non quick release: Fixed with the axis screw.Material: IronColor: BlackSize: 11cm x 6cm x 4cmPackage Contents:1 x Cycling Derailleur Guard ProtectorOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.