This 79' is in over good condition. It is missing the lower back plate, and the bass EQ knob on the first channel. Plenty of headroom, and a great overdriven tone if you prefer to turn up!
The Pro (originally called the Professional) is one of Fender's oldest amp designs. Like other Fender amps, the Pro evolved in the '50s and '60s with different cabinet styles. In the mid-'60s the Pro was replaced by the Pro Reverb, and the design was changed to the Silverface style in 1973.