Multifunction firmer chisel with interchangeable blades, to use as a traditional firmer chisel. 3 widths of cut: 18, 20 and 22 mm in only one tool. Saving of place and weight in the toolbox: one tool instead of 3 chisels. And furthermore, a tool always perfectly sharpened. The change of knife is done in few seconds. The removable blades can be resharpened.