Punch Unit 25 Pin Connector. Cut-out and mounting slots are punched in one operation. Drill only one 7/16" (11.1 mm) pilot hole. Use with Kwik Stepper® step bits. Fast, accurate panel punching with no sawing or filing required. Universal size punches for front or back mount of TRW Cinch and ITT Cannon-type or equivalent connectors in 9, 15, 25, 37 or 50-pin configurations. U.S. Patent No. 4,899,447.