Features and Benefits: Forged from the finest chrome molybdenum alloy steel – the best choice for strength and durability; Radius corner design – to extend the life of fasteners; Design drives the side of the fastener instead of the corner; Provides increased strength, but also avoids rounding of rusted or damaged fasteners; This is an Impact socket. It is 27 mm. It is 6 point and 1/2 in. drive.