this Swan 510X Crystal Controlled External Oscillator with 10 Crystal Sockets (includes 3 Crystals) Is In Excellent Condition.

 This unit was marked for use with the Swan 350C, 500C, and 500CX transceivers, to provide out of band coverage.

The frequencies of the three included crystals are 4590 KC, 10020.3 KC, and 3.3095.

Other than a small spot on the top that has been touched up, there are no bad marks or scratches.

I have not used this unit as I do not have the radios it works with.

I am selling it as is as described for the family of a silent key.

You can read about this unit as well as all the other Swan gear at the link below:

https://mmg-garden-rr.webs.com/Documents%20-%20Ham/SwanCompendiumRev4.pdf