Reed internal pipe cutters cut pipe from the inside (i.e. drain pipes or sprinkler drops, etc). Heat-treated steel, saw-toothed blades on the internal pipe cutters make for fast cutting. Available in a variety of sizes and styles, all internal pipe cutters fit in a standard 3/8" drill. During use, flats on the larger cutters keep the cutter from slipping in the jaws of the drill while a lock washer on the smaller cutters keeps the blades from slipping. All saw-toothed internal pipe cutter models cut plastic pipe aggressively and can cut wood for sink lugs.