1939 advertisement from Jewelers' Circular Keystone magazine of the Gallet MultiChron 30 "Clamshell", the world's first water resistant chronograph wristwatchReverse view of the Gallet Clamshell showing the 4 screws that compress the 2 part case around the flared acrylic crystalOpen view of the Gallet Clamshell showing top part of the two part case and complex Swiss column wheel movement1939 Esquire Magazine print advertisement of the Gallet Clamshell
The Clamshell, manufactured between 1936 and 1951 by the Gallet Watch Company of Switzerland, is the world's first water resistant wrist chronograph.[1][2]
