These top of the line, 2.5″ 4-part grinders by Sharpstone are made by the high-pressure extrusion method – rather than by computer numerically controlled (CNC) tool and cutter grinder. This results in much stronger teeth as there are no stress or fracture lines in the metal. The handle folds flat when not in use and each grinder is supplied with a cotton drawstring bag in which to store it.