This is the official Grundig brand hand microphone for the 3110 series Grundig dictators and transcribers. It uses the proprietary Grundig plug, so no other brand hand microphone can be used with the unit.
So you have one of those old tape transcribers and you need a dictation microphone for it. This plugs into any Grundig transcriber or desktop recorder.
On the Grundig 800FX you can control start, stop, record and playback mode, rewind, fast forward, end of letter and indexing. The dimensions are 10.2 x 5.2 x 3.9 inches and the desktop stand (cradle) is included. Grundig makes a full line of micro cassette transcribers and desktop dictators. They are the last manufacturer to make micro cassette dictation equipment.
If you are stubborn and don't want to change to digital, this is the only solution for a slide control on a desktop dictation recorder.