Sunex 244xd 1/2-Inch Drive 1-3/8-Inch Extra Deep 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, 1-3/8-Inch extra deep impact socket