Besides the rich and affluent who globe trotted to Europe and such places, Rolex was little known in the states prior to WW2. Because of an agreement with Aegler (who supplied most Rolex movements and most of Gruen's movements) Gruen was to have North American market and Rolex had the rest of the world.
Being the keen business man that he was, Wilsdorf diversified and started the Oyster line as a RWC product. Oyster was for North America. Oyster watches were cased in RWC cases, but with Fontmelon movements. (Not Aegler)
Fontmelon movement (Not my picture... I'm too lazy to remove the back tonight.):
The United State's first RWC watch was a RWC watch branded for Abercrombie & Fitch. Back in the day Abercrombie didn't sell skinny jeans, but would outfit you for a Safari or Polar Exbition. These watches were cased in nickel chromium and didn't hold up like stainless steel.
Canada received RWC's Oyster line. Here is my Oyster Lipton (Tea Stain) which was a Canadian market watch. Usually supplied by the families of Canadian servicemen who joined the fight in Europe. Note the military time 24 hour track.
In the late 30s, a Portland Oregon based jewelry store wanted to sell a rugged man's watch that could stand the test of nature.
Wilsdorf obliged and supplied the Zell Brothers with watches.
I guess Portland has always been weird. The Oyster name was not adopted, but instead another critter with a strong protective exoskeleton was chosen. . .the turtle.
Enter the Zell Bros' Turtle
Timer by RWC. 
I've wanted one since I learned about them. Luckily the dial appears intact beneath the crazed 83 year old acrylic crystal. . .
Also with the 24 hour military dial.
This was Virgil's watch.
Thankfully he inscribed the back of the watch with his name and Oregon National Guard number.
He apparently married Julia in 1942 and went off to war with this watch. He returned and lived a long life. He is buried near my grandfather.
Thanks for your service Virgil and for keeping this piece of history alive.
