The harmonium has thus become an integral part of Indian Music. The keys are played and bellows are compressed simultaneously. Bina 3¼ octave double reeds 5 stopper single bellow 39 keys standard harmonium the seller is bharatcultura and is located in this country in. Harmonium is a musical instrument which is a free-reed organ that generates sound as air flows past a vibrating piece of thin metal in a frame.