The Garmin Forerunner 255 is now 43% at Amazon, bringing this excellent GPS all-rounder to its lowest-ever price.

Not literally, of course. But the legendary watch owes its popularity—if not its underwater cred—to everyone's favorite spy.

Originally designed for wartime use, scuba diving took off as a recreational sport in the early 1950s. Those with the means and the time to engage in subaquatic recreation required a few pieces of ...