This is a mid-70s Fender Silverface 4x12 combo amp. Basically a 4x12 Fender Twin.
This is the master volume with gain boost switch model, which I think was around 1976, before the ultralinear models came out.
It's very loud and clean. I believe these are the original speakers, although I do not like them at all. I have used the amp through other speakers, and it sounds amazing.
This was kind of busted up when I bought it; the cabinet was starting to come apart at the joints, but I've repaired it with lots of wood glue and compression.
The original reverb tank was no longer working, so I replaced it with a new one from MojoTone.