Jaeger-LeCoultre Memovox Polaris
A diving watch with an alarm meant to be heard underwater.
The Polaris could ring to warn the diver when it was time to surface. The caseback had holes and a membrane that let the sound out. The model returned in 2018.
Materials: Stainless steel; self-winding alarm movement
Manufacture: Made in Le Sentier; the caseback was designed to carry the sound.
The crowns for time, alarm and the inner ring.
The inner rotating ring for dive time.