Sea-Dweller 16600 Polizia di Stato

The Sea-Dweller was developed in the late 1960s in partnership with COMEX, the French deep-sea diving company, for saturation divers who spent extended periods in hyperbaric chambers breathing helium-oxygen mixtures. The helium escape valve — a Rolex patent that allows helium molecules to exit the case during decompression without blowing off the crystal — was the Sea-Dweller's defining innovation and the feature that separates it from the Submariner. Rated to 1,220 metres (4,000 feet) in its current form, the Sea-Dweller has always been the Submariner's more capable, less glamorous sibling — a watch designed for professionals who needed more than 300 metres of water resistance and weren't concerned with whether it had a Cyclops lens.

The ref. 16600 'Polizia di Stato' was made in 2008 as a limited run of 78 pieces for the Italian State Police (Polizia di Stato). It features the CNES logo at 9 o'clock and a special, engraved, caseback.