To cut lock pockets for mortise locks; is simply operated with a standard drill (with 13mm drill chuck). New version; now also easy to use on rebated doors. Due to the extra wide housing, all door thicknesses can be worked on without any modifications. Mortises for security strike plates are also possible. DBB 1 Drilling Jig with 3 Cutters (CWB16, CWB20, CWB24)