This is the new Sinn 613 St UTC dive watch, it’s rated to a depth of 500 meters (50 ATM or 1,640 ft), and it has a dual time display to show two timezones simultaneously.
This isn’t just a dive watch in name or style, it has a stopwatch function with its 60-minute stopwatch display and a diver’s bezel to allow for the exact monitoring of dive times. It also has Sinn’s Ar-Dehumidifying Technology integrated, to stop it from misting or fogging internally.
This is the new Sinn 613 St UTC dive watch, it’s rated to a depth of 500 meters (50 ATM or 1,640 ft), and it has a dual time display to show two timezones at the same time.
History Speedrun: Sinn Spezialuhren
Sinn Spezialuhren was founded in 1961 by Helmut Sinn, a former World War II pilot and flight instructor, in Frankfurt am Main, West Germany. The company was initially focused on manufacturing navigation clocks and pilot chronographs for professional use – the company’s early products were designed strictly for functionality and reliability above all else.
Helmut Sinn took an unusual direct-to-consumer approach, bypassing retail markup by selling watches through catalogs and directly to customers, a model that helped the company build a loyal following among professional pilots who often valued quality over brand name prestige.
Through the 1970s and 1980s, Sinn specialized in pilot’s chronographs and mission-ready tool watches. The company used proven Swiss movements from Valjoux and Lemania, concentrating its resources on tough cases, excellent dial legibility, and reliability under extreme conditions.
The Sinn 140 chronograph became one of the company’s best-known models when German astronaut Reinhard Furrer wore it aboard the 1985 D1 Spacelab mission. The watch’s performance in space helped give the brand a major credibility boost, and it introduced the brand to many Germans for the first time thanks to the extensive media coverage.
In 1994, Helmut Sinn sold the company to Lothar Schmidt, a former IWC engineer and production head at A. Lange & Söhne. This marked a key turning point in the company’s historic timeline – Schmidt brought deep, modern manufacturing expertise and an emphasis on engineering and innovation. Under his leadership, Sinn introduced several proprietary technologies that further elevated the company’s profile, bringing it up to the level of some of the best-known Swiss watchmakers.
The Sinn 613 St UTC dive watch is a new-for-2025 design from the storied German watchmaker, it’s a tool watch in every sense of the term, and it has an enviable water resistance rating down to 500 meters (50 ATM or 1,640 ft).
Among the most influential were Ar-Dehumidifying Technology, Tegiment surface hardening, and Hydro Technology – which makes Sinn dive watches so equipped completely legible underwater from any angle and pressure-resistant beyond traditional ratings.
Another new Sinn innovation, DIAPAL, replaced lubricated escapement parts with friction-free materials, extending service intervals significantly and increasing accuracy over extended periods of time.
Sinn engineers and designers created the Einsatzzeitmesser (EZM) line, translated as “Mission Timer” – these were tailored for elite units like the German GSG 9 counter-terrorism group and specialized fire brigades. The EZM series was built with professional feedback from personnel and focused on extreme durability, magnetic field resistance, and maximum readability.
The direct sales model remained, and Sinn kept production largely in-house in Frankfurt, including its quality control and case fabrication. The company gradually increased international availability through a small number of authorized dealers, but retained its independent, engineering-first philosophy.
Today, Sinn is respected as one of the foremost tool watch specialists in the world.
The Sinn 613 St UTC Dive Watch
The Sinn 613 St UTC dive watch is a new-for-2025 design from the storied German watchmaker, it’s a tool watch in every sense of the term, and it has an enviable water resistance rating down to 500 meters (50 ATM or 1,640 ft).
The watch has a bead blasted stainless steel case with a matching case back, it’s topped with a sapphire crystal with an anti-reflective coating top and bottom, and there are versions with either the stainless steel bracelet or rubber strap.
The watch has a bead blasted stainless steel case with a matching case back, it’s topped with a sapphire crystal with an anti-reflective coating top and bottom, and there are versions with either the stainless steel bracelet or rubber strap.
Inside you’ll find an SW 535 automatic mechanical movement with 23 jewels and 28,800 semi-oscillations per hour. This movement offers dual-timezone functionality and a date function, as well as a 60 minute stop watch at the 6 o’clock position.
The watch is now available direct from Sinn through their online store here, and it comes with a three year warranty and international shipping.
Images courtesy of Sinn Spezialuhren
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.