This 40-piece Carbon Steel Tap & Die Set is perfect for creating or repairing threads on screws, bolts, and more. Made from heat-treated carbon steel for durability and strength, it comes complete with a handy storage case. The set includes a Tap Wrench (M3 - M12), Die Holder (M25), Screwdriver, and various Pitch Gauges including M3 x 0.5, M3 x 0.6, M4 x 0.7, M4 x 0.75, M5 x 0.8, M5 x 0.9, M6 x 0.75, M6 x 1.0, M7 x 0.75, M7 x 1.0, M8 x 1.0, M8 x 1.25, M10 x 1.25, M10 x 1.5, M12 x 1.5, M12 x 1.75, and 1/8-27 NPT. The set is also described as heavy-duty, heat-treated, rust-resistant, and precision-machined.