An air impact wrench is a socket wrench power tool driven by compressed air. An air impact wrench, also called a rattle gun because of the sound it makes, is one of the most common pneumatic tools found in the automotive workshop (and on the racetrack). Its most familiar use is removing the nuts from a wheel so that a tire can be replaced. The air impact wrench delivers a great deal torque, which is often needed to twist the nuts free. A valve controls how much torque is applied. The tool can be set to spin in either direction.

An air impact wrench should not be used for fine tightening of wheel nuts. If the nuts are put on too tight, the bolts may fail while the vehicle is moving, causing the wheel to shear off. An air impact wrench should also used only be with specially hardened impact sockets, extensions, and joints. The sockets are special 6-point types which can stand the sudden force that the wrench generates.