The Rolex COMEX submariner was specifically designed with the professional diver in mind. It was custom made during the latter part of the 1960s for the underwater operations specialists COMEX (compagnie maritime d’expertises). The problem COMEX faced was a combination of extreme depth water resistance and explosive decompression caused by helium entering the inside of the watch.  This problem was solved when Rolex added a helium escape valve to the watch at a the nine o’clock position. This valve  would slowly release the pressure in order to match atmospheric pressure. All the COMEX edition submariners were personalized with the COMEX logo inscribed on the dial of the watch and on the back of the case.  The first prototypes of the watch were released on a trial basis between 1969 and 1971. These watches were given the model number 5513. However the valve on the watches was a little crude and not made of stainless steel and therefore wore out due to oxidation. After the trial period Rolex began to manufacture special 5513s especially for COMEX and were given a new model number 5514. This time round the valves were smaller and made of stainless steel which solved the problem Rolex faced in the trial. The COMEX submariners were made in very limited quantities and have become a very desirable watch for collectors and enthusiasts alike. Fitted with the Rolex Oyster bracelet the owner enjoys a smooth and secure fit and can be confident with Rolex's superior build quality. Rolex bracelets may have in excess of 100 moving parts, invisible to naked eye. This superior craftsmanship and fine finishing earn it the right to be called a Rolex bracelet.