Gun Drill BitsDrill Bit 5A Carbide Tip Hole Saw 12-120mm Drill Bit Set Hole Saw For Stainless Steel Metal Alloy Drilling 1PcsSee the second picture for detailsPrecautions:1. Check whether the center drill is tightened, turn on the machine and check the concentricity of the hole saw. When drilling, place the hole saw perpendicular to the metal, otherwise the alloy will fall off easily. It is best to use cutting fluid to cool down the thick metal2. Please follow the drilling speed table when drilling, otherwise it is easy to damage the hole saw3. When using a hand drill, make sure that the hole saw is perpendicular to the metal, it is best to use a bench drill to operate