I have one of them, can't say I ever used it, I remember a different unit that I would measure long distances with. Have on clue what it's worth, I'm thinking either junking it or putting it on the display section of the office, it's been out in the shed and that may be getting torn down soon. I figure no one is interested in it but I even have a manual.?ÿ
One very occasional use is if you need to set up a "monitor" to be left on site, so that a non-critical movement can be detected. Place it firmly aimed at prism on object. Set it away on tracking with a truck battery attached, telling site foreman what the displayed reading should be. Forget about it for a month.
You wouldn't risk that with a modern instrument but an old unit has no book value. Ours is a good one - will measure 5k on a triple prism, so can be left in a safe place out of harms way.