Sunex 220fp 1/2-Inch Drive 5/8-Inch Female Pipe Plug 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, 5/8-Inch female pipe plug socket