When I joined we had those on some of our front line aircraft too. It was a real revelation when they were upgraded to a radio where the pilot could actually dial VHF frequencies.
Some of the older UHF ones still had real crystals inside. Due to the very limited number of "studs" available, if going out of area we had to ask the engineers to "recrystallise" the radio, to allow us to speak on the frequencies we needed.
