ROLEX - Helium escape valve opens when the difference in pressure between the inside and outside of the watch reaches 3 to 5 bars, allowing helium to escape, thereby protecting the watch. #
Why do diving watches need a helium escape valve? - Chrono24 Magazine
Helium escape valve – Watch-Wiki
The Helium Escape Valve - Everything You Need to Know | Bob's Watches
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Rolex Genuine & Rare Sea-Dweller 16600,16660 watch Part Helium Escape Vacuum Valve 24-V53-2 New
Insider: Rolex Deepsea Sea-Dweller D-Blue Dial ref. 116660 a.k.a James Cameron. Built like a Marine Tank and Exceptionally Beautiful. — WATCH COLLECTING LIFESTYLE
Dossier: History of the Rolex Sea-Dweller - Revolution