For the removal of damaged screws, stud & bolts. Left hand drill bits remove fasteners or creates the pilot hole required for a screw extractor. If the LEFT HAND DRILL does not remove the fastener, the hole drilled becomes the preparation for a screw extractor. The opposite direction flute enables the broken fastener to be gripped and wound out of the hole and also permits reverse drilling, which stops the fastener being driven tighter. Ensure drill is run in reverse