These drill bits work with a very high accuracy and very low tolerances, thus high-precision work with a high tool life time is possible
We recommend to use these drill bits for UNC, UNF, BSP, BSW, BSF helicoil thread inserts installation, as they ensure exact size of the core hole needed
They can be used to drill new core hole or enlarge existing hole of the damged thread insert. They are also suitable for the universal use where exact hole sizes is required
To be used in materials such as steel, cast steel, cast iron, graphite, brass, aluminium and bronze
The cutting direction is right and the point angle is 118°. DIN 338. Cylindrical shank
Available in sizes from 2-56 to 1"1/2-12 (equivalent diam. 2.4 - 48.50 mm) 
If you are instead looking for general-purpose drill bits not specifically designed for wire thread inserts, you can find them at the following link: Drill bits, complete catalog, available both as individual bits and in complete sets