Bi-Metal Hole Saw, Actual Hole Size 1-3/8" (35.0 mm). Cut through steel, tin, aluminum, fiberglass, wood and plastic. Deep 1-5/8" (41.3 mm) cutting depth allows for cutting through 2" x 4" wood studs. Extra-tough bi-metal blade- we use the highest grade oftool steel to outlast competitor's blades. That beats premature saw replacement and saves you money. Steam oxide finish - no paint to gum up and slow cutting. The saw runs cooler for longer life and better performance. Extra-thick backplate minimizes vibration for smoother, easier, less tiring cutting. Made in USA.