For drilling cylindrical holes in solid material up to a thickness of 4mm, Idea tool for sheet metal workers, electrical contractors, auto mechanics, panel beaters and general contractors, Drilling perfectly round holes in steel, brass, copper, aluminium, wood and plastic. This set contains a 5 - 22mm (3/16 - 7/8”) and a 6 - 35mm (1/4 - 1 3/8”). HSS with a hard titanium coating offering longer life, the coating provides less friction and thus less generated heat. 2 piece. Hang-sell.