One Switchcraft adapter for converting old lap steel guitars, Astatic JT-30s and other mics with old fashioned screw-on connectors to 1/4". Screws onto the 5/8-27 threaded output end found on most old Astatic JT30 microphones. With this adapter installed you can simply plug in a conventional 1/4" guitar cord and you're good to go. Nickel plated brass body and coupling ring. This connector does not fit bullshit new imported copy of Astatic JT30.