This air operated power draw bar comes complete with a 3/4 socket. It uses your stock milling machine draw bar, and if your draw bar is not a 3/4 inch db, you can use any size. Socket you desire, the butterfly impact is a 3/8 in model. This power draw bar will fit bridgeport and most other import. Also included is a pressure regulator unit, you simply bolt the power draw bar to the top of your mill using three 1/4-20 bolts, and connect the air supply, the regulator is preset to 90 psi, which is the maximum for this butterfly impact, and believe me its more than enough pressure to the job.