No batteries required

Spent the morning clearing out out all sorts of paper records spanning too many years. It takes forever shredding on a machine that's built for occasional light use. But, I gotta at least make an effort to avoid any potential identity theft issues.

However, I did come across this little beauty, and even though I'm being ruthless about throwing stuff away, there is no way I will get rid of this.
In the days before electronics, this is how I did my calculations out on the shop floor, almost 40 years ago. It brought a big smile to my face when I first came across it today and memories came flooding back.

And it only took me two minutes to remember how to use it.

Ah well. Until tomorrow....