The DEWALT DWA1814 7/8" (22mm) Hole saw features improved bi-metal material that extends life and speed in all applications. An improved plug ejection allows user to remove plug faster and the double tooth design strengthens each tooth for longer life and improved durability. It offers thick, hardened backing plates which prevent thread stripping. Deep cut style hole saws will cut 2x material in 1 pass. The increased high speed steel height (highest in the industry) improves hole saw durability. Common applications include: Plumbing- entrance holes into junction boxes and through drilling for conduit/Mechanical and Plumbing-through holes for pipe, T- joints into pipe/ HVAC-through holes for pipe, conduit/Pipe/Sprinkler Fitters-saddle cuts into pipe for T- joints. Hole saw size: 7/8", Max speed: 390 rpm.