What you have here is a Fender Dual Showman TFL5000D Reverb: the Fender Twin's circuitry, but with more power (100w instead of the Twin's 85) and added flexibility (2 speaker outs, so you can plug in 2 8-ohm cabs and knock a building down). This is the classic head that was used by everyone from Hendrix to Fleetwood Mac to early Zeppelin – bright as the sun and loud as hell.

My understanding is this is a '71 (the transformer is dated '69) – the much-sought-after pre-master-volume version. I just got it serviced by the pros over at Chicago Music Exchange, and it has an upgraded 3-prong grounding cable. Hoping to find it a good home!