Spring steel punches place a 1/4" diameter hole 1/2" from the end of Allstar’s 1" x .062" thick spring steel material. Built-in stop positions material for accurate hole placement. ALL23116, placed on a hard surface, can be struck lightly with a 3 to 4lb. hammer. ALL23117 may be placed in a vise, or handheld and impact driven, using a 3/4" socket to punch spring steel mounted to race car.