17mm off-road wheel & tire set. 1 set = 4 tires & 4 wheels. Tires DO NOT come installed. You will receive one set of wheels with standard tires + the upgrade off-road tire kit. You must install the tires. For 1/64 scale cars. Maybe more difficult to install. Experience required. Axle modifications will be required in many cases. Install carefully not to damage wheel. Use lubrication to help install carefully.