Versatile kit for creating new threads, chasing existing threads, or repairing damaged threads on a wide range of metals including aluminum, brass, bronze, cast iron, mild steel, carbon steel, stainless steel and more. Premium quality Industrial grade hardened GCr-15 alloy steel construction provides high strength and durability, and it meets ANSI/ASME B1.1 standards for guaranteed quality. Excellent cutting performance All cutting teeth are precisely CNC machined and accurately heat treated to Rockwell hardness 60 HRC for optimal threading performance. Most popular sizes Includes a full range of most commonly used tap and die sizes for UN-Series threads: - Coarse Thread (UNC): #4-40, #6-32, #8-32, #10-24, #12-24, 1/4-20, 5/16-18, 3/8-16, 7/16-14, 1/2-13 - Fine Thread (UNF): #10-32, 1/4-28, 5/16-24, 3/8-24, 7/16-20, 1/2-20 - Pipe Thread (NPT): 1/8-27 Use scenarios - Automotive and machinery maintenance: repair stripped threads or chase new threads in engine components, brackets, housings, or fittings. - Fabrication and DIY projects: create or repair threads in aluminum, steel, or cast iron stock for reliable assemblies. - Repairs in diverse materials: restore accurate threads in stainless steel, carbon steel, or other common metals to ensure proper fastener fit and function.