This has a twist drill bit inside, with the sharp carbide teeth it's perfect for fast cutting off clean round holes :)The gears is made from carbide steel and designed in a sharp and solid way,in order to make the product more stabilized and service long with lower consumption.It suitable for hand held electric drill,stand motor driven drilling machine and mobile ribbon type magnetism drilling machine.Cutting quick and precise holes in stainless steel, mild steel, iron, copper, brass and wood.Material : Carbide steelColour:As the picture showsDepth it can drill : Approx. 20mmLength : 7cmOutside Diameter25mm Note : Only include 1 piece Package includes : 1 x Carbide Tip Metal Cutter 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 +/- 1-3 cm.