These days, wrist watches are hard to justify wearing; digital clocks are everywhere, and they’re generally always correct.
But a Mil-Spec watch, made specifically for our military personnel, that’s got clean looks and pure function as its purpose, along with Tritium gas-lit phosphor tubes marking the time in complete darkness (for years!) is very hard to beat. Light-weight and comfortable, I use mine in place of much more expensive world-nameplate Swiss watches that sit unused (a special kind of tragedy).
These watches are tools and, I think, very cool, and I believe they fit under the Cool Tool umbrella with their own unique panache. The dial has “US Government” and a radiation symbol, too. Hard to beat.