Dialgraph Biorythym Calculator to calculate your peak performance days

This is a vintage, mechanical (like a circular slide rule) device to calculate your biorhythms- suppose to find your “best and not so” days. I used it to try to see if I was having a bad day when I had a car accident. Fun to investigate yourself. Comes with the complete manual.

Condition: Used · Seller: wagner125 · 100.0% positive · 272 ratings

View on eBayMore Similar

Affiliate disclosure: we may earn a commission if you buy through this link.