The Bosch Metric Tap and Die Set (BTD40MS) features a wide range of taps (including Plug taps), dies and assorted wrenches and accessories. Plug taps are ideal for cutting right-hand internal threads. They are the most widely used type of tap, with three to five threads chamfered for general-purpose applications. Dies cut right-hand external threads. They are commonly used for threading rods, bolts, and studs. Made from heat-treated carbon steel, these are rust and tarnish resistant tools. The rolled threads are more accurate and cleaner than machined threads. They are tooled to the most exacting specifications to ensure that your bolts anchor securely. Laser-etched marking ensures accurate size identification.