DEWALT D180022 1-3/8-Inch Standard Bi-Metal Hole Saw The product is 1-3/8" 35mm Bi hole saw Easy to use The product is manufactured in China Double tooth design strengthens each tooth for longer life and improved durability Sharper tooth geometry cuts material faster for faster drilling Thick, hardened backing plates prevent thread stripping Deep cut style holes saws will cut 2x material in 1 pass. Increased high speed steel height (highest in the industry) improves hole saw durability