A simple self-centring jig for cutting mortises for door locks. Drive shaft accepts 1/4" shank router bits or Porter Cable style mortise cutters. Not for use with routers. Maximum depth of cut: 150mm, sliding length is variable by adjusting clamping heads vertically. The height gauge hooks on top of a door or it can be inverted to set the unit at a pre-set height over the floor. Power drill and cutting bit not included.