This unit was built in the 1970's, some say 1980's. I do not have particular knowledge about guitar tube amps but I was able to do some electronic repair testing and replacing some parts. It has a metal box attached to the amp unit that seems to be some  either a tremolo or reverb device inside with some very sensitive springs that vibrate when playing with the knobs.  It plays well according to the settings and volume level used, using a very old electric guitar I have had around for quite some years. All functions seems to be in good conditions, all knobs and pots are in good condition. The front grill has a hole. The speakers have some rust on the metal but work without flaws. See pictures for more info.