Bi-Metal Hole Saw, Actual Hole Size 1-1/8" (28.6 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 Minimize