This is a 1970's harman/kardon Model 930 Twin Power Receiver. The Twin Power name is not some marketing gimmick; the 930 has dual power supplies, one for each channel. If you notice the two large transformers in the pictures (the second interior picture) it’s essentially like having a mono amp for each channel. The h/k 930 was the first solid state receiver to utilize dual mono amps in its design. The 930 features a Contour switch, similar to a loudness switch, where the lower frequencies will get a boost relative to the high frequencies. Brand : Harman Kardon Model : 930 Twin Power Finish : Silver/black/green Year : 1970 Made In : United States Condition : Excellent Condition Shipping method : TNT/FEDEX/DHL