Museum of HP Clocks
leapsecond.com
leapsecond.com
I didn't know it at the time, but these still go for $1500+ on ebay. A new equivalent performance unit would be $5000+. Only downside is it's huge (4U rackmount) and weighs 80 lbs.
In my mind Agilent/Keysight is the real HP and the current HP just a PC-related spin-off.
http://www.cliftonlaboratories.com/Bill%20Hewlett%20and%20hi...