Features: Brand new and high quality Metal brake disc, outer diameter 16mm, inner hole 8.4mm It needs to be used with 22MM metal wheels hubs, if it is smaller, it will catch the wheel hubs High precision machining, stable and reliable Replacement the original damaged parts, ensures long lifetime and better work performance Nice spare parts to upgrade and modify your cars Packing includes: 4 x Brake Discs(PCS) Note: The metal steering cups of some mosquito vehicles are thicker and need to be polished and installed, and then fixed with 502 glue. Some plastic steering cups are thinner, so apply a little double-sided tape and then fix it with glue