The tools main body is a 17-7 PH stainless steel heat treated to a spring temper. The S shaped gate is tempered spring steel. The pivot bushing is case hardened. Every part is nickel plated.The tools main body is a 17-7 PH stainless steel heat treated to a spring temper. The S shaped gate is tempered spring steel. The pivot bushing is case hardened. Every part is nickel plated.When using the tool, make sure the S shaped gate is turned fully clockwise. This engages the front face of the tool giving it great support. Hook the tools onto the first course in such a manner that they support the board you are placing on them about 3ft in from each end (if it is a 12ft length).If you place the tools towards the ends it will allow the center of the board to sag (really). Now if you place a tool on the board that sagged, you run into trouble.Now that everything is in place, place a nail about 1/2in down from the top of the siding into the nearest stud from the tool. leave this nail about 1/8in proud. Do the same for the other tool.Now twist the S shaped gate counter clockwise 90 deg. Push up on the tool and pull the siding out enough to release the tool. Go ahead and nail off the board to the manufacturers specs. Don"t forget to sink the two nails left proud.