Circular Slide Rule

[rprosperi]

These things are cool and very satisfying. You don't need a fidget spinner when you have one of these. Joe Horn posted some excellent photos of his, plus some of a slightly different slide-out insert from one of mine.

https://holyjoe.net/hp/600-st.htm

These came in several slightly different styles, but in MANY different colors and logos from all kinds of manufacturers in the 60's. They were high-end marketing giveaways for large or important customers and were treasured by the owners.

These show up regularly on eBay with wildly erratic prices ranging form $20-$100.