SCREW SLOT FILES by FRIEDR. DICK GMBH are designed for precision in making screw slots, offering six sizes and two styles for various slotting needs.
The product includes a matched pair of files, one Joint File for edge cutting without widening the slot, and one Equalling File for cleaning and squaring the slot sides.
Files are 5-5/8" (14.3cm) long, very thin, and must be handled with care as they can be easily bent or broken; no guarantee on the files is provided.