DEWALT 2X LONG LIFE Hole Saw Bi Metal 3 5/8 Inch, DWA1858. Features DEWALT 2X LONG LIFE Hole Saw Bi Metal 3 5/8 Inch. A deep-cut hole cuts twice the material in a single pass. A double-tooth design strengthens each tooth. An improved plug ejection system enables users to remove plugs quickly. DEWALT Bi-Metal Hole Saws power through 2 times the material in a single pass. A sharp tooth geometry expedites cutting, and thick, hardened backing plates helps to prevent thread stripping. A high-speed steel height makes them ideal for tough jobs.