On October 30 1925 Paul Perregaux and Georges Peret took out a Swiss patent for a moisture-proof winding-crown No. 114948. They sold their rights to Wilsdorf who obtained a British patent No. 260554 usually considered the original Oyster patent. In October 1927 Mercedes Gleitz swam the Channel for the first time while wearing the famous waterproof Rolex Oyster wristwatch.