Impact wrench

An impact wrench uses an internal hammering mechanism to deliver short, rapid bursts of rotational force to a fastener, rather than the steady, continuous torque a drill or driver applies. Those quick impacts let it break loose a rusted or overtightened bolt that would stall a standard drill or strip a driver bit trying to force it.

This makes impact wrenches a common tool for jobs like removing lug nuts, suspension bolts, or other fasteners that see high torque and road exposure. Because the tool can generate very high torque very quickly, it is easy to overtighten or even snap a fastener if you rely on it for final tightening instead of finishing critical bolts with a calibrated torque wrench.

Impact wrenches are sized by drive size, most commonly a 3/8 inch or 1/2 inch square drive, and by their maximum torque output, and both should be matched to the fasteners you actually work on. A common mistake is buying based on torque numbers alone without checking that the drive size and available sockets match the intended use, whether that is automotive work or general shop tasks.