Sinn 156 and Sinn 156b

Sinn 156 is often referred as the successor of the Heuer bund, a watch used by German airforce pilots. Unlike the Heuer Bund, the Sinn 156 was never issued, as the era of pilot watches was already over by its release. Sinn 156b is a divisive pilot watch due to its size and movement. It is a large watch with 43mm diameter and 51mm lug to lug. Its movement, Lemania 5100 with central minutes, is considered a workhorse and provides an alternative for all the Valjoux 7750 powered chronographs.

Sinn 156 was in production for nearly two decades, and it came in two references 156 and 156b. Aside from the reference difference, there are a lot of variations, some which I will try to list in this post.

Basic Information

MovementLemania 5100
Lug to lug51mm
Lug width20mm
MaterialStainless Steel
Water Resistance100 m

Dial, Bezel and the Movement

The dial layout of Sinn 156 is defined by the Lemania 5100 movement; three sub-dials and day/date. Chronograph hands are typically bright red. In contrast to Valjoux 7750, Lemania 5100 has central minutes, which leaves one of the sub-dials free from chronograph usage. The sub-dials are as follows:

  • (top) sub-dial 24h display,
  • (left) seconds dial,
  • (bottom) chronograph dial

All of the Lemania 5100s that I have owned have had distinct winding sensation and they are truly a pleasure to wind, serviced or not. The movement is considered a workhorse, but due to limited parts availability, I would not run unserviced Lemania 5100. The chronopushers of the Sinn 156 are similarly stiff to Valjoux 7750 and they make a satisfying crunch when triggered. The movement itself is not the prettiest.

The bezel of the Sinn 156 is anodized aluminium and it rotates smoothly both ways. The plastic crystal sits one to two millimeters above the bezel. The bezel develops wear just from rotation and winding the watch over time. The bezel is particularly vulnerable to contact with rocky surfaces. It is very typical to find watches where the paint has completely worn off from the sides of the bezel.

Worn paint at the side of the bezel.


Luckily, Sinn still has parts for the Lemania 5100 movement. The price of movement service of my Sinn 156 was 675 euros including shipping in December 2020. It is unknown whether Sinn has the capability to produce more parts for the Lemania 5100 and how long their parts supply will last. However, Sinn has produced watches with Lemania 5100 up until 2008, so it is possible that they have quite a bit of parts still left. Other manufacturers, such as Fortis and Tutima have had to stop servicing Lemania 5100, and Omega still has parts for their cal 1045, which was used at least in Speedmaster Mark 4.5.

The screw-down crown of the Sinn 156 is short, so one must take care not to break the threads. The crown of my Sinn 156b was replaced during service, and the replacement was identical. From parts scarcity angle, I’d say the overall serviceability of Sinn 156b is good.


The key difference between Sinn 156 and 156b seem to be the ‘Military’ print on the dial. Both Sinn 156 and 156b were produced with tritium dials, but Sinn 156b after 00s started to come with Luminova dials. The tritium compound on these watches seems to develop a very desirable orangish patina and it is rare to see watches with broken or tarnished tritium. To me this is a tell of good case construction.

The bracelet of the early 156s were the Sinn branded NSA bracelet. These bracelets are now very sought after and go on auction sites for over 600 euros. The later H-link bracelets are also rare to find loose, so it is best to buy a complete watch, if one intends to wear the Sinn 156 on a bracelet. I haven’t found a definite answer whether end-links from other watches will fit the Sinn 156 and it is best to assume they don’t. However, it looks like it is possible to file Sinn 103 end-links to fit the Sinn 156, but they won’t be a perfect match. Similarly, the hollow end-link bracelet from EZM2 can be fitted to a Sinn 156 case, giving another alternative for those who want a steel bracelet.

Most Sinn 156 and Sinn 156b came in a monocoque case, but some of the later Sinn 156b came in a screw-back case. The monocoque cases are interesting, since the case containing the movement is attached to the frame with screws that has the lugs. Some watches also have lug-holes, which in my opinion is a desirable feat in a watch.

TritiumSinn 156/Sinn 156b
Lug-holesSinn 156/Sinn 156b
‘Military’ print on dialSinn 156b
Screw-back caseSinn 156b
NSA braceletSinn 156
H-link braceletSinn 156b

Sinn 156 was also produced for Bell & Ross and there is a Beams version as well. Other manufacturers such as Hamilton and Bulova have produced a very similar watch, but it is unclear whether the Hamilton / Bulova watches were made by Sinn.


Sinn 156 is a big watch with a fun movement and cool looks. Depending on the configuration, it can feel very vintage to very modern. Watches with NSA bracelet and full tritium are the most sought after, but watches with luminova dials can make excellent everyday wearers. With the Sinn serviceability, the watch is relatively care-free.

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