Sinn

Who are Sinn?

Sinn Spezialuhren is a German watchmaker in Frankfurt am Main, founded in 1961 by the pilot Helmut Sinn and owned since 1994 by the engineer Lothar Schmidt (Swisswatches Magazine; WatchTime). It makes pilot’s watches, diving watches and chronographs built around its own technical standards. This page covers its history, collections and ownership, then what to check when buying a pre-owned Sinn in the UK.

Sinn buys its base movements from Swiss makers, including Sellita, La Joux-Perret and Concepto, and modifies some of them itself; those carry SZ calibre numbers (Swisswatches Magazine). Many of its cases, including those in submarine steel, are made by SUG, a case maker in Glashütte (WatchTime). The company sells direct from Frankfurt as well as through dealers (WatchTime).

The history of Sinn

Sinn’s history runs from a pilot’s small business selling cockpit clocks and chronographs to a maker of tool watches with its own technologies. The key dates are the founding (1961), the 140 S in space (1985), Lothar Schmidt’s takeover (1994), the first in-house technologies (1996 to 2003) and the TESTAF and DIN 8330 pilot-watch standards (2012 and 2016).

Helmut Sinn. Helmut Sinn, born in Metz in 1916, was a Luftwaffe pilot and blind-flying instructor who had also sold cuckoo clocks and been the German importer of Heuer chronographs and stopwatches before starting his own brand (Swisswatches Magazine; SJX Watches). He founded Helmut Sinn Spezialuhren in Frankfurt, making navigation cockpit clocks and pilot’s chronographs (Wikipedia). Wikipedia says these were made in Switzerland under a private label and sold direct to customers. Sources differ on the start: Worn & Wound and SJX Watches both say he created the business in 1956, while the company’s own statement, quoted by Worn & Wound, gives 1961.

Space. In 1985 the astronaut Reinhard Furrer wore a Sinn 140 S chronograph, with a Lemania 5100 movement, on the Spacelab D1 mission (Swisswatches Magazine). A 142 S went with Klaus-Dietrich Flade on the Mir-92 mission in 1992, and a Sinn chronograph flew on the D2 mission aboard the space shuttle Columbia in 1993 (Swisswatches Magazine; Wikipedia).

Lothar Schmidt. Lothar Schmidt, an engineer who had been production manager at IWC Schaffhausen, began working with Sinn on 1 September 1993 and took over the company a year later (Swisswatches Magazine; WatchTime). WatchTime also reports that in 1990 he helped build up production at A. Lange & Söhne in Glashütte. He renamed the business Sinn Spezialuhren GmbH and moved it towards research and its own technology; the first new line was the 244, in titanium (Swisswatches Magazine; WatchTime). In 1996 he acquired the Swiss watchmaker Guinand (Wikipedia). Helmut Sinn died in 2018 (Wikipedia).

Technologies and standards. Between 1996 and 2003 Sinn introduced HYDRO, Ar-Dehumidifying, DIAPAL and TEGIMENT, described below (Swisswatches Magazine). In 2012 it created TESTAF, a technical standard for pilot’s watches, with Aachen University of Applied Sciences. At Sinn’s suggestion the German standards body DIN set up a working group, and DIN 8330, a standard for pilot’s watches, was published in March 2016 (Swisswatches Magazine).

Sites. Sinn moved into new headquarters in Frankfurt-Sossenheim in 2017 and opened a service and assembly branch in Dresden on 17 May 2022 (Swisswatches Magazine). Its case maker, Sächsische Uhrentechnologie Glashütte (SUG), was founded by Lothar Schmidt and Ronald Boldt on 17 December 1998, according to WatchTime; Swisswatches Magazine gives 1999.

What is Sinn known for?

Sinn is known for tool watches built to measurable standards: pilot’s watches tested to TESTAF and DIN 8330, diving watches in German submarine steel, and its own technologies for keeping cases dry, hard-wearing and readable under water. The details below are each sourced.

Ar-Dehumidifying technology. Introduced in 1998, it slows the ageing of the movement’s oils caused by humidity. The case is filled with a protective gas, sealed with special EDR seals, and fitted with a drying capsule of copper sulphate that changes colour as it absorbs moisture (Swisswatches Magazine).

HYDRO. HYDRO watches are filled with oil, which keeps the dial readable from any angle under water. Because the oil would stop a mechanical movement, they use quartz movements (Swisswatches Magazine). Our guide to mechanical and quartz watches explains the difference.

TEGIMENT and submarine steel. TEGIMENT is a surface-hardening process for cases and bracelets, first used in 2003 (Swisswatches Magazine). The U-series diving watches, from 2005, use German submarine steel (Swisswatches Magazine), and Wikipedia states the U2 is rated to 2,000 metres and protected against magnetism to the DIN 8309 standard.

DIAPAL and magnetic protection. DIAPAL, from 2001, removes the need for oil on the pallets of the escapement (Swisswatches Magazine). Sinn added magnetic field protection in 1994 (Swisswatches Magazine).

Mission timers. Sinn calls its EZM watches Einsatzzeitmesser, or mission timers, made for special forces, fire services, divers and pilots (Wikipedia). The UX S Kampfschwimmer became the service watch of the German Navy’s special forces command in 2015 (Swisswatches Magazine).

Which Sinn collections are there?

Sinn’s range is organised by model number rather than by name. It includes pilot’s chronographs (103, 356), pilot watches (104, 857), space chronographs (140), sports chronographs (144), the Frankfurt Financial District watches (6000), mission timers (EZM) and diving watches (U, UX and T series).

The collections table gives a one-line description of each. A few points help when you are reading listings:

• Read the full reference. Sinn identifies watches by number and suffix, such as 103 St, 140 St S or 857 UTC TESTAF (Swisswatches Magazine). The suffix often marks a different version, so check it against the listing.
• Movement types differ. HYDRO models such as the UX use quartz movements rather than mechanical ones (Swisswatches Magazine), so check which a listing has.
• Materials. Besides steel and titanium, Sinn has used Damascus steel since 2010, Argentium since 2022 and Goldbronze 125 since 2023 (Swisswatches Magazine).
• Water resistance. Ratings vary widely between models: the T50 is rated to 500 metres and the U2 to 2,000 metres (Swisswatches Magazine; Wikipedia). Our guide to water resistance ratings explains what they mean in use.

Who owns Sinn?

Sinn Spezialuhren is privately owned by Lothar Schmidt, who has been its owner and managing director since he took it over in 1994. In a 2024 interview with WatchTime he said the company is planned to pass to a foundation in due course.

Schmidt bought the company from its founder, Helmut Sinn, on 1 September 1994 (Swisswatches Magazine). WatchTime describes him as “Inhaber und Geschäftsführer”, owner and managing director (WatchTime, March 2024). The company is not listed.

SUG, the Glashütte case maker that produces much of Sinn’s case work, is a separate company. WatchTime reported in 2020 that Lothar Schmidt raised his stake in it to 74 per cent after the 2002 floods, and that about half of SUG’s capacity goes to Sinn. Swisswatches Magazine describes SUG as a subsidiary, so sources differ on how the two are linked.

Buying a pre-owned Sinn in the UK: what to check

Check that the reference and serial number match the papers, which technologies the watch has and whether they have been serviced, and that the watch is not recorded as stolen. Then decide what guarantee you need, because a dealer’s warranty and Sinn’s own guarantee are different promises.

1. Papers and the full set. Ask exactly which papers come with the watch and whether they are originals. Our guide to what “full set” means explains what each item proves and what it does not.

2. Reference and version. Check the full reference, including any suffix, against the listing, because one model number can cover several versions (Swisswatches Magazine). A seller who will not show the numbers before you pay is a reason to walk away.

3. The drying capsule. On a watch with Ar-Dehumidifying technology, look at the drying capsule: it changes colour as it absorbs moisture (Swisswatches Magazine). Ask the seller when it was last checked or replaced.

4. Authenticity. Buy from a seller who will put authenticity in writing and accept returns, and have the watch checked by a watchmaker you choose. Our guide on how to spot a fake watch covers what a watchmaker looks at.

5. Stolen-watch check. Before you pay, check the serial number against a stolen-watch register and ask the seller to confirm the watch is not reported lost or stolen. Our stolen-watch check guide lists the UK registers.

6. Servicing and warranty. Ask when the watch was last serviced and by whom. Lothar Schmidt told WatchTime that all watches have to be sent to Frankfurt for service, and that Ar systems are also fitted by partners in the USA and Japan. The length of Sinn’s guarantee, and whether it passes to a later owner, depends on Sinn’s terms. A dealer’s own warranty is a promise from the dealer, not from Sinn. See watch warranties explained.

7. Who you buy from. There are three main routes:

Sources: WatchTime, interview with Lothar Schmidt (26 March 2024); Swisswatches Magazine, a visit to Sinn (checked 29 October 2026).

If you buy from Sinn in Frankfurt or another seller in the EU, the watch is an import into Great Britain and VAT and duty can apply; our guide to import duty and VAT on watches explains how.

For the full process from setting a budget to collecting the watch, see the guide to buying a luxury watch.

Frequently asked questions

When was Sinn founded?

In 1961, in Frankfurt am Main, by Helmut Sinn (Swisswatches Magazine).

Who owns Sinn?

Lothar Schmidt, who bought the company in 1994 and is its owner and managing director (WatchTime).

Is Sinn a German or Swiss brand?

German. It is based in Frankfurt am Main, although its base movements come from Swiss makers (Swisswatches Magazine).

Does Sinn make its own movements?

No. It buys movements from Sellita, La Joux-Perret and Concepto, and modifies some, which carry SZ calibre numbers (Swisswatches Magazine).

What is Ar-Dehumidifying technology?

A system from 1998 that keeps a watch dry inside, using a protective gas, special seals and a copper sulphate drying capsule that changes colour (Swisswatches Magazine).

What is TESTAF?

A technical standard for pilot’s watches created by Sinn and Aachen University of Applied Sciences in 2012. It led to DIN 8330, published in 2016 (Swisswatches Magazine).

Has a Sinn watch been to space?

Yes. Reinhard Furrer wore a Sinn 140 S on the Spacelab D1 mission in 1985 (Swisswatches Magazine).

Why do some Sinn diving watches use quartz movements?

HYDRO models are filled with oil to stay readable under water, and the oil would stop a mechanical movement (Swisswatches Magazine).

Where is a Sinn serviced?

Lothar Schmidt told WatchTime in 2024 that all watches are sent to Frankfurt for service.

This page is general information. Watch60 is independent and has no commercial relationship with Sinn Spezialuhren.

We check the facts on this page against the sources listed, and it is correct to the best of our knowledge as of October 2026. Brands change their warranty, servicing and sales terms, so confirm them with the brand or the seller before you buy.