... tiped hole saws (Core Bits)with case.You can cut the following size holes 4mm, 5mm, 6mm, 8mm,10mm,12mm ... 35mm, 38mm, 40mm, 45mm ,50mm 55mm, 60mm. ENGINEERED TO CUT HOLES IN GLASS, TILES, SLATE, MARBLE ,GRANITE with ease!!! Best ... OFF. I PERSONALY USE A PIECE OF WOOD WITH THE SAME SIZE HOLE IN IT AS A GUIDE , WHICH ... CAN BE HELD OR CLAMPED TO THE JOB. UNTILL IT STARTS TO DRILL THEN I REMOVE ...