Cooper Hand Tools, a division of Cooper Industries, Inc., manufactures and markets many well-known brands of hand tools, chain, and electronic soldering products, including Campbell (R) chain, Crescent (R) brand wrenches and pliers, Lufkin (R) measuring tools, Nicholson (R) files and saws, Plumb (R) hammers, H.K. Porter (R) bolt cutters, Weller (R) soldering products, and Wiss (R) snips. Headquartered in Raleigh, North Carolina, Cooper Hand Tools has manufacturing facilities in 16 international locations, and has approximately 4,400 employees worldwide. Used to restore damage or worn external threads on bolts, pipes, etc. Each thread restoring file will work with 8 different thread sizes Convenient 4-piece set Color caps on tubes Type 1 black cap: Regular bolt; 11-12, 13-14, 16-18, 20-24 TPI Type 2 red cap: Ex. Fine/ex. Coarse bolt; 9-10, 12-16, 20-27, 28-32 TPI Type 7 green cap: Regular pipe; 8-10, 11-1/2-14, 16-18, 24-27 TPI Type 8 blue cap: Metric Bolt;. 75-1.0, 1.25-1.5, 1.75-2.0, 2.5-3.0.