Exact item shown, HP time interval standard - shown in the catalog as a way to compare and measure waveforms against a trusted standard. Last calibrated in Sept 1998. I don't have a better standard than the oscillator that this has so I can't confirm calibration - I cleaned the switches so it now operates reliably - the photos show several different timing selections - the distortion is due to the cables (BNC isn't my favorite) and the scope I'm using. The last photo is a catalog page about this standard and how to use it, courtesy of the HP Archive.
I've set the price at what it's worth to me to have a frequency standard handy when I need/want one. This will fit safely into a medium flat rate box if I remove the feet - you will just have to clip them back in place when the unit arrives. Note to me: under analyzer desk.Check out my other items.