Iron or steel units, with a "C" structure in which are located the punch, the die and the blank holder. The punch slides in a cylinder with cup springs to perform the extraction of the punch, independently from the ram of the press. There are different types of units, which are distinguished from each other depending on maximum diameter; maximum thickness; for flat or profiled sheet or plate; depending on the maximum distance between the center hole and sheet metal edge. Replacing punch and die, the same unit can process round holes, or shaped as rectangles, slots, square or other geometries. More units can be mounted together on a base plate, in order to realize several holes in a single shot.