The first water resistant wristwatches were not developed by the perfect fake Rolex, but in fact it was promoted by Rolex successfully. As early as in October 30, 1925, Paul Perregaux and Georges Peret invented a patent of the crown and the reference number was 114948.
They designed a technology of crown seal that prevented moisture from entering the case, using springs and spirals to essentially prevent moisture from entering the case from the crown for the first time. Hans, Rolex’s boss, recognized the importance of the patent and quickly negotiated with patent owners to persuade them to transfer it.
The popular Rolex Oyster copy watch with silver dial was the rudiment of diving watches which was the earliest model to be used to promote the water resistant watches. The shape of the case is quite different from modern Rolex.