High-quality material: Bike trailer hitch is made of 5mm thick carbon steel with one-piece molding process. There is no welding as a whole, and it is durable, rust-free and non-deformable. Universal design: The axle hole diameter of the bike trailer hitch is 12.2mm. Can be used on most bikes and works with most child trailers, pet trailers and grocery trailers. Suitable for QR axles and solid axles up to 12.2mm (OD≈0.48in). Easy to install: The bike hitch is easy to install, first connect the bike trailer hitch to the bike with a nut, make sure it does not rotate when tightening, then pass the Allen key through the pin hole and fix it in place while tightening, must tighten it for safe use. Safe and flexible: The bike clutch is not easy to open and will not loosen by itself. To ensure the highest level of safety during riding. Whether your bike is riding on a flat or bumpy road, the trailer will not wobble or overturn easily. What you get: 2 x Bike Trailer Hitch, 2 x Connecting Pins.