Armeg Electrician Set 5 Piece where standard Hole saw thread patterns for convenient use with industry standard drive arbours set includes 1 x 20 / 25 / 64 / 73mm, 1 x 9.5mm Hexagon Shank Arbor, 1 x 13mm Hexagon Shank Arbor, Bi-Metallic Hole saws can be used in steel, stainless steel, non-ferrous, wood, plastics.