Greenlee 825-2-1/8 Bi-Metal Hole Saw, 2-1/8-Inch Cut through steel, tin, aluminum, fiberglass, wood and plastic Deep 1-5/8-Inch cutting depth allows for cutting through 2-Inch by 4-Inch wood studs Extra-tough bi-metal blade Steam oxide finish with no paint to gum up and slow cutting Extra-thick back plate minimizes vibration for smoother, easier, less tiring cutting