Czech small airborne radiotelephone, especially made for gliders. There are 4 crystal controlled channels, about 0,5W AM TX power, average RX sensitivity, squelch. The radio runs from a 12V NiCd battery pack. Almost fully transisorised, except the TX final stage - there is the only one tube in the radio.
The radio is in the working order, unforunately incomplete - there are an accumulator box, microphone, speaker and antenna missing. I saved two of those radios from devastation (diassembling for the parts) in children's radio club ... sorry to say, some irreplaceable parts are lost forever this way. (Luke 23:34)
There is a complete service documentation in my collection.