The Hillman Zinc Round Combination Head Machine Screw is used with nuts or screwed directly into a threaded receptacle to fasten metal parts together. Fasten the machine screw with a screwdriver to reduce risk of over-tightening to protect the screw and fastened material. If nuts are needed, use these combination head screws with nuts of the same finish and threading for proper fit. To obtain the fastener length, measure from the underside of the head, to the tip of these stainless steel machine screws. Measured from the underside of the head to the tip of the screw to obtain fastener length Use for any indoor or outdoor projects 1/4 in. x 1-1/2 in. machine screw Engineered to fasten metal parts together Nut of the same finish and threading is included for proper fit Round head combination drive for ease of installation Fasten these stainless steel machine screws with a screwdriver to reduce the risk of over-tightening 5 combination head screws per pack