Chicago Pneumatic S421M - 1/2 Inch Square Drive, 21 mm, Standard, Shape B, 6 Point, Impact Socket

DURABLE: Chrome-molybdenum Steel and Phosphate manganese surface finish for extreme wear resistance, maximum torque, and preventing fastener rounding. Easy to read laser etched marking with output size, and model number. ENSURE SAFETY: Impact sockets (made with Molybdenum chromium steel) are designed to support and absorb the momentary shock of each impact, therefore preventing cracks or breaks, and prolonging the life of the socket. ACHIEVE OPTIMAL EFFICIENCY: Impact sockets provide a perfect fit to powered tools, and therefore will avoid unusual deformation or damage to the tool's square drive.