A variety of HC49 style units with pins or wires. Some have glass cases. Units 20-60 MHz are usually 3rd. overtone types while those above 60 MHz are 5th. overtone types.
All must use an appropriate resonant oscillator circuit. Overtone crystals can be used on their fundamental frequency (10 - 20 MHz).
Crystal collected over many years, some ex equipment, some little used from old projects. Frequency accuracy could be low.
All units tested for oscillation in fundamental mode before dispatch.
For frequencies above 50 MHz see separate listing.