If you need to add a panel-mount connection for telephone-interfacing projects but don't have the time or ability to cut a custom oval or square hole, this RJ-50 Panel Mount Plug is the easiest and fastest way to panel-ify your existing phone kit. It's about 30mm in diameter so you can drill a hole in your wood, plastic, or metal with a common hole saw or bit; no special shapes or filing are required. Unscrew the plastic nut, insert the plug, and re-attach. Ta-da: Now you have a pass-through RJ-50 jack.