exact item shown, Ball Efratom Division Crystal Oscillator Model ESXO serial # 1023.  See spectrum analyzer plot - I tested it at 18V, 20V and 24V, I couldn't see any difference, it's probably a 24V unit.  SMA output.  It's interesting that this has been out of warranty for just over 30 years 

Note to me: top drawer small cabinet

I normally ship within 24 hours of your order, but the post office does not always initiate tracking when I put the packages in the drop off box.