Here is the opportunity to acquire a rare Sinn (Heuer) 1550SG / 155 3H dialed watch, which I bought at an auction a few years back.

The Sinn 155 is marked “1550SG” between the lugs, and the story is that Sinn bought the remainder stock parts from Heuer back in the late ‘70s / early ‘80s.
The age of this particular 1550SG is unknown.

Please find below a detailed description of the watch, but also have a good look at all photos for your reference.

Photo album here: https://www.watchuseek.com/media/albums/1550sg.33071/

The good stuff:
The dial is extremely well preserved, and has just the most minimal marks of aging which is very hard to see with the naked eye. The tritium of the Arabical numbers is evenly aged and the creamy color is very nice. The tritium hands are also very nice with excellent tritium patina and show no cracks or missing tritium pieces.

The watch runs very good with about 2 days running time after hand wounding it.The crown is unmarked but is tight and turns excellent. The chrono works as it should with crisp pushers. I do not not know the time difference since I do not have the right equipment to measure this.

The plexi is very good with no visible marks on it, I just polished the minimal swirls out with polywatch.

The bezel is in excellent condition with hardly any marks either, and turns both ways with good friction.

Than the less good stuff:
Unfortunately this 1550SG does not have a Valjoux 230 movement but a Valjoux 23. The Valjoux 23 lacks the famous flyback function.

I had a conversation with the auction house about the movement. They got in contact with Sinn in Frankfurt and it was explained to me that back in the days almost all Sinn 155 Heuer watches were delivered with Valjoux 230 but it in very little occasions it could be that also Valjoux 23 movements were installed. Reason was not given to me, but it is likely that the stock of spareparts were not always sufficient to install the 230.

About the chrono function: It does not completely resets to 12. The bund second resets about 20% between minute 60 (12hr) and minute 1 (so let’s say about to 20/100 of a second) visible on the photos but you have to look carefully, it is a very minor offset.

Also, the case of the watch is polished. I have no idea if it was originally delivered polished by Sinn, but I do know Heuer 1550 SG watches are not polished. Of course the polishing could have been done by someone afterwards.

For a 40+ year old watch, all in all I believe it is a beautiful watch with a lot of history. Despite the polish it is in excellent condition.

On the photos, the watch is mounted to different straps.

The watch is sold as watch only, without a strap, but I can include the Diaboliq camouflage canvas strap with black buckle for a little surcharge.
Unfortunately no box nor papers.

Than the price.
It is hard to price this watch because they rarely come onto the market, but I am looking for 4950 Euro, but I take the equivalent in US$ which comes to 5400 USD

I have seen a non 3H version for sale in Germany for €6900 not long ago.

The price includes full insured tracked shipping world wide.
I ship with postnl.

Please find attached a lot of photos. Most photos are made with an iPhone 11 Pro, some with a Olympus PEN F.

Please contact me in case you have any questions.
I am a private seller.

Condition: used, but very good vintage condition
Movement: Valjoux 23, handwound
Crystal: plexi domed
Case: ttainless steel case
Dimensions: 43mm diameter, ??mm height
Caseback: 4 screws
Crown: not screwed
Dial: black dial
Strap/bracelet: without
WR: ?? meters