This is a Crown model SSMS mono reel to reel preamp from an SS700 with a microphone preamp input.
It comes with a power cord so you can use it as a stand alone microphone preamp without the deck.
You can plug a microphone into the front panel or the back. I tested it with a microphone and it was
had a lot of gain, but was a little noisy. I did not test it with a recorder.