Size 1 mm up to 4 mm, two drills in each tube.Rolled flute with high elasticity and a low risk of breakage due to manufacturing process.Oxide coating reduces wear still with good and rapid chip removal.Drill bits have a cylindrical shank and designed for use in drill stands and drill drivers.High-speed steel (HSS) drill for drilling in bronze, brass, carbon steel, cast iron and alloy steel.Manufactured to DIN 338