Lose track of time underwater, and you could lose your life when your oxygen runs out. Luckily, the Eterna KonTiki Diver watch saves you from your own absentmindedness. It uses technology from the automotive industry to stay waterproof at 3,280 feet without tightly screwing down its winding stem (a step that users often forget with other mechanical diving watches).


The face lifts to reveal the waterproof stem.

Eterna created a miniature version of a shaft seal, the hollow, doughnut-shaped collar around each shaft in a car’s transmission. In a car, the seal prevents high-pressure oil from leaking out. In the KonTiki, it keeps high-pressure water from seeping in. As water pushes on it, the hollow tube flattens out to hug the stem more closely, forming a tighter seal as pressure builds. That makes it more effective at great depths than the O-ring seals in other watches. So it will keep on ticking, and so will you.