Seat tube reamer body threaded 20x2 to mate up to the seat tube reamer arbor. Black oxide conversion coated drilled and threaded for the 1018 black oxide conversion coated steel handles (not included). NOTE: The body mates to the seat tube reamer arbor to perform manual seat tube reaming and also to the Art. 31 series 188mm. long seat tube reamers for machine seat tube reaming.