An excellent set for car repair and tire shops. The sockets in the set have spiral teeth. which can be used to unscrew over-tightened bolts/nuts. We also recommend using the set in cases where the bolt/nut head is worn and there is a risk of over-tightening. The sockets are suitable for use with sizes 17-19-21-22 mm, i.e. the most common wheel nut/bolt sizes (also Asian cars). The sockets are made of a special chrome-molybdenum alloy. Phosphated surface treatment. In a plastic box.