A powerful little circuit with surprisingly good audio quality. Can transmit up to about 1/2 mile in open country. This is probably the most powerful FM transmitter that you can legally purchase. An electret microphone is used to add sensitivity. The circuit can run on six volts; greatest output is at 12 volts; but use 9 volts and short antenna wire to stay legal. (our 80-065 Varactor tuned unit is considered the best kit of this type. Need a stereo unit? See 80-085)