Description: 1/2-inch drive, 12mm triple square spline size. Made of premium chrome molybdenum steel for superior hardness and great rust resistant. Black phosphate finish to resist corrosion. Sockets designed with a pin hole for use with pin and O-ring systems for secure socket retention. (O-ring and dowel pin are inclusive.) Wide application in DIY hand-making, household maintenance, and most general repairs. A must-have addition to any electric power drill or impact driver.
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