From trucks and tractors to heavy equipment and large machinery, big service and repair jobs need the TEKTON 5-pc. 1/2 in. Drive Deep Impact Socket Set. Engineered for use with impact drivers, each socket has a 6-point opening that snugly fits the hex shape of fastener heads, allowing it to apply maximum torque without slipping. To prevent round-off under stress, it grips the flat sides of fastener heads rather than the corners. Easy to read even in low light, the large, high-contrast size markings are permanently laser etched into the steel surface. The through-hole in the drive end of each socket locks onto the tang of impact wrenches or drivers so it won't fall off or stick on fastener heads. To protect against rust and corrosion, the black phosphate finish absorbs and holds oil, repelling moisture.