The 12-28 TPI SAE thread restoring file is suitable for pitches 12, 13, 14, 16, 18, 20, 24 and 28 per inch. The .7-3MM TPI thread restoring file is suitable for pitches .75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.5, and 3mm. These files restore damaged or rusted external threads on bolts, threaded shafts, pipes and pipe fittings. The profile shape is of the files is square. Overall length is 8-1/2-inch. Sizes are clearly marked.