This product in display is an automatic center punch. Made of steel. Size: (length: 5-1/2 inch, body Dia: 3/4 inch). Used to produce a dimple in a work piece. It performs the same function as an ordinary center punch but without the need for a hammer. When pressed against the work piece, it stores energy in a spring, eventually releasing it as an impulse that drives the punch, producing the dimple. The impulse provided to the point of the punch is quite repeatable, allowing for uniform impressions to be made.PLEASE CLEAN AND APPLY OIL BEFORE USE.