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. It is very suitable for using to cut holes in a of materials including steel, brass, wood, plastic, etc. : Titanium The 4 Cutters Come in the Following Sizes: 3-12: (3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm) 4-12mm: (4mm, 6mm, 8mm, 10mm, 12mm) 4-20mm: (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 14mm, 16mm, 18mm, 20mm) 4-32mm: (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm) Colour: Black Material: High Speed Steel Package Contents: 4 * Step Cone Drill Bits Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.