The BlueSpot 3 Pce Step Drill Set is specially designed for precision drilling of holes in aluminium, brass, copper, plastic, steel and wood. Manufactured from high speed steel for increased durability and cutting power. Titanium coated to reduce friction and heat. 2mm step increments. Set contains: 4-12mm in 2mm increments, five-step drill, 4-22 in 2mm increments, ten-step drill and 4-32mm in 2mm increments. Set is supplied in a robust metal case.