Drills more precisely Can drill through reinforced concrete and the hardest of natural stone - One Piece solid carbide 4 cutter - head - Three Piece solid carbide 4 cutter - head - Optimum 4 x 90 degree symmetry, all 4 carbide cutting head - Four Flute Design - Easy centering tip facilitates spot drilling Bit Dia (D) mm / 22 Total length (L1) mm / 250 Working length (L2) mm / 200