Sunex 217zm 1/2-Inch Drive 17-mm 12-Point Impact Socket Forged from the finest chrome molybdenum alloy steel-the best choice for strength and durability Radius corner design-to extend the life of fasteners The design drives the side of the fastener instead of the corner Provides increased strength, but also avoids rounding of rusted or damaged fasteners 1/2-Inch drive, 17mm, 12 point impact socket