I am the second owner of this unit - it was originally installed in a recording studio. The unit has been well cared for and everything about it is in perfect working condition with no visible physical flaws. General info:ELECTRICAL: 50w/ch stereo. 100w mono. Response 20-20kHz (+0 -0.25dB). Distortion 0.25%. Noise and hum -90dB. Output impedance 4, 8 and 16 ohms (2, 4 and 8 ohms mono). Damping factor 10. Input impedance 200k. Input sensitivity 0.5v. Sentry Monitor.MECHANICAL: Chrome chassis. Output barrier strips. Audio inputs. Gain controls. Mono-stereo switch. AC outlet. Circuit breaker. Output socket.Size 7-1/16"H, 10-5/8"W and 15-5/8"D. Weight 35 lb. Sold from 1967-1979.