HEAVY DUTY TUNGSTEN STEEL ALLOY: The tap and die set is made of hardened tungsten steel alloy. These heat-treated taps and dies with accessories are manufactured to be very hard, with high strength and increased durability to be used for several years without replacement. THREAD AND TAP EFFICIENTLY: With these metric taps and dies, easily use the taps to cut a thread inside a hole or form female portions of mating tools like nuts. The heavy-duty dies cut or form a male part like bolts. Our metric tap and die set is designed to help perfectly cut damaged internal and external threads. UNIVERSAL TAPS AND DIES: These high-quality taps and dies can thread any metal with efficient results. Solid metals that can be tapped or threaded include aluminum, brass, carbon alloy steel, cast iron, and bronze. These hardened thread sets are relatively easy to use, offering less fatigue, and have high resistance to corrosion and wear. PACKAGE CONTENTS: Our thread and tap set includes 7 different sizes