Nutsetters impact lobular screw head 5/16 inches length 6 inches Lobular nutsetters are built for maximum durability, performance and long life with impact tools. Designed to drive the fastener from the side, rather than forcing the corners to turn, maintaining the true shape of the fastener and dramatically reducing breakage and damage from stripping. Also provides more clearance on the corners of the fastener where paint build-up often occurs. Black oxide finish resists corrosion to increase the life of the nutsetter.