Sean Charlesworth joins us in the Tested office this week to share one of his prized possessions: a Curta mechanical calculator. Designed in the 1940s before electronic calculators, this hand-cranked device was considered the the most precise pocket calculator available, and was used by rally car drivers and aviators.

Learn more about the Curta Calculator here:
http://curta.li/
http://en.wikipedia.org/wiki/Curta