This is the New HSS Steel Large Step Cone Drill Titanium Bit Set Hole Cutter, which is made from high quality HSS steel, and with the Titanium coated to reduce friction and heat. 4-32mm (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm).