Old fashioned device for converting logarythms to distance; people used to pay as much as two or three hundred dollars for them in the days when a new Porsche could be had for $3000.
Slide rules...
ebay ‘em!
:-)
I can't recall how much I paid for my Post Versatrig© in 1966. But making $2.25/hr (min wage) as a Draftsmen Trainee ('apprentice') I know it was a good part of my weekly take home pay.
I still have it, the Instruction Manual and Case too. All pristine condition. Turned out the simpler one sided, Post© model 1447 (Bamboo body) I had was adequate for most of my calcs then. Which btw is also in Pristine condition, its right in front of me now ;)
Both are prolly worth a pretty penny now.
Logarythms? Logarhythms? anyway they started about $5.