These are the barrel type switches that screw onto the JT-30 type screw-on connectors. It's 1.75 inches long from end to end and have a threaded (male) end and a female end that screws directly to the mic. The switch has a clear plastic button that can be held in momentarily in the “on” position, or you can push it in and slide it up to lock it in the “on” position. Just slide it down to turn off.
Great addition to your gig case to be used with or without your volume control and superuseful in feedback situations or between songs or sets to be sure your mic is off while maintaining current VC setting for that gig.
This was tested and works perfectly. Cosmetically it has some light tarnish. Overall awesome condition for this vintage rare harp mic connector.