Designed for square drives - You can use the PRO Impact socket insert for hex screws, bolts, and nuts with your square drive wrench. We developed it for screw work in extensive assemblies or other demanding industrial tasks. The PRO Impact socket insert is made from heat-treated chrome-molybdenum steel and is highly resistant to high torque due to its thick walls. The black phosphate coating protects it from rust and corrosion. The socket inserts are laser-etched and color-coded, making it easy to find the right one at a glance. They feature a groove and a through hole. For extra strong hold, they can be secured to your impact wrench with a pin and ring.