The "Senna" S/EL Watch Spotter's Guide - S25.706C/S25.706/CG1123

After purchasing my early version S25.706C, I went into Nerd Mode and carefully inspected the differences between this version and later versions of the watch. All can be considered the "Senna" version S/EL ana-digi cream dial, but Senna wore the original release, as shown in the 1990 catalogue.

The versions that followed have had subtle changes done, which I'll detail here.

The OG Senna S/EL ref. S25.706C

Pictured below is Senna's actual watch. Top picture from the Bonham's Auction site, when his watch was auctioned for the 2nd time in 2007 (first auctioned in 2004). Bottom picture, showing the case back of Senna's watch, from the Authenticity Paper (Signed by McLaren's Jo Ramirez).

Things to note, which will change with subsequent versions:
1. Bezel - The Triangle is slightly different and the bezel Font is thick. The way to easily spot the font difference is the "50", the bottom loop tail of the "5" ends very close to the top half of the "5", almost a closed loop
2. Dial - It only has "200 METERS", the "Swiss Made" is outside (or below) the red ring, and the Font used on all the dial markings is slightly thicker than later versions. Also, it has a lume dot just below the 6 o'clock seconds register.
3. Case - Has a satin smooth finish
4. Strap - Is Dark Brown and has "Cuir Veritable" (French for Leather Genuine) on the underside
5. Case-Back - Has "S25.706C" above the logo and the finish is polished
EDIT: It seems some have serial numbers to the right of the case-back's TH logo, while others do not. (My theory is that TH may have started initial production without, then added serial numbers as a running model change.)
6. Movement - ETA 251.251

The first thing to change was the bezel. Here's another S25.706C, but the bezel is the style which will be found on later versions. Note the Triangle is broader, the "5" on the "50" is less bold and the tail loop of the 5 is more open. It's unclear if this was a running model change or if some of these have had their original bezels replaced when serviced.
I noticed that @Snowy's S25.706C has this newer style bezel, while mine has the OG bezel like Senna's.

First Revision S25.706
This version is very similar to the CG1123.

Things to note:
1. Newer style bezel, with broader triangle and less bold font. You can see the "5" on the "50" is the newer style font.
2. Dial now has "Professional" added above "200 METERS" and the "Swiss Made" is inside (or above) the red ring. The font on all markings on the dial is slightly less bold. Lume dot at 6 o'clock is now gone.
3. Case is the same, still with a satin smooth finish
4. Case-Back now has a matte finish and the reference number is below the logo. Also, the "C" suffix (for Calf or Cuir) is dropped; 0459 (or BC0459) is the new designation for the brown leather strap but not shown on case-back

Incidentally, metal bracelet versions of the OG S/EL Ana-Digi carried the "M" suffix. From what I can tell, the OG S25.706C was never offered as a S25.706M with metal bracelet. It was with this First Revision S25.706 that it seems the two tone bracelet would become an option. OTOH, the original grey dial S25.206M and white dial S29.006M were only offered with metal bracelets at initial release. Senna must've specially requested his grey dial with the brown strap.


CG1123
This version is almost the same as the previous revision S25.706.

Things to note:
1. Bezel - newer style, same as the First Revision S25.706
2. Dial - Same as First Revision S25.706
3. Case - No longer a smooth satin finish, it has a fine brushed surface. This is the biggest change.
4. Case-Back - CG1123-0 instead of S25.706 (TH changed their reference number scheme for all S/ELs around 1993)
5. Movement - Changed to ETA 251.252 (But I've been told there's no notable difference from the ETA 251.251). I suspect some First Revision S25.706 watches might have this 251.252 movement and/or perhaps some CG1123's might have the 251.251.
--

One final change to look for is the brown strap. The S25.706C/S25.706/CG1123 were all originally sold with a dark brown leather strap. However, many owners of the Metal Bracelet version have since swapped out their bracelets for the BC0459 brown leather strap. Or, as original straps became worn, they were swapped with newer replacements. These newer straps are a lighter shade of brown and have "Genuine Leather" on the underside rather than "Cuir Veritable".

For example, this TAG Heuer image shows an OG S25.706C but the strap has been replaced with the newer lighter brown version. If you look at any picture of Senna wearing his OG, it's always a dark brown.

In Netflix Senna, Gabriel Leone is also wearing the newer lighter brown strap.

My detailed comparison was done using my own watches. As I now own a model from each variation.

Original S25.706C (Top L), First Revision S25.206 (Top R), CG1123 (Bottom L), and CG1111 (Bottom R).

Out of curiosity does the case back of your s25.706c have a serial number engraved on it. I purchased one off eBay a few months back after I saw the dial. However, my case back does not have a serial as far as I can tell.

Yes, it does. Here's a pic of my S25.706C. I've edited my photo to obscure part of the serial number for privacy. But you can see that it's engraved vertically to the right of the TH logo shield.
To my knowledge, all authentic S/EL watches should have the serial number engraved in this same location. See this thread:

Do you think the gold is always finished the same? It looks matt in some of the pictures and polished in some...?

Here's a rare special edition for you...... 20 pieces commissioned by a certain 7-time F1 champion as gifts ..

Thanks, Mspeedster. That was my concern. Unfortunate for me but it was worth the risk.

Yes I believe the gold is always polished. Senna wore his TAGs as tool watches, they're all pretty scratched up. Which is why I think they look matt in some pictures.

That's an awesome piece, is it yours?

I have conflicting feelings about that one. Great for Schumacher fans. But as a Senna fan, 1994 was not a happy year.

1992 Mexican F1 Grand Prix, picture borrowed from instagram

Belongs to a friend who was on his crew in 1994. He gifted the mechanics on his car this one at the end of the year

I was thinking more of two of the pictures you used in your original post, but looking at them again they look like renders. My two tone SEL is polished (and scratched).

Yeah, the two head on shots are TAG Heuer images. I think the photos are touched up using filters and whatnot to enhance the image, rather than computer generated renders per se.

Here's another TAG Heuer image of a S25.706C. Surely touched up as well, but shows more of the mirror polish on the gold bits.


Here's one of Senna wearing his Grey dial, in which the gold looks sorta matt to me and is an example of what I thought you meant.
BTW, the same differences for the OG Cream dial S/EL ana-digi and its follow-on versions also apply to the Grey dial ana-digi. The only difference is I don't think a S25.206C (Grey dial with Brown Leather strap, like Senna's) actually existed for sale. Most likely, Senna's OG Grey dial was a S25.206M with the strap replacing the stock bracelet. I've searched for S25.206C but can only find images of the S25.206M, or the first revision S25.206 or CG1122.

For what it’s worth I’ve attached some crude photos of the “s25.706c” I bought from a Japanese seller off of eBay back in October. Not sure if there are more red flags outside of the missing serial. Based on the great research @Mspeedster compiled above the 5 on the bezel would suggest this might not be an earlier model. So that plus the missing serial doesn’t leave me feeling great about my purchase but let’s wait and see I guess.

I think you might be OK, based on @mattp showing his early S35.406C doesn't have a serial number either. Matt has collected many vintage 80s TAGs, so I think he'd know if he had a fake in hand.

From your pictures, most things look correct. The bezel change may have been more random and not necessarily a sign of one watch being older than another. I've seen S25.706Cs with both types, but noticed that Senna's personal one had the closed loop 5; the 1990 catalogue also showing this bezel. Your strap does look like it was replaced with a newer spare, but still an authentic OEM strap (BC0459).

One thing that wouldn't be easy to fake is the movement. The 1/100th split seconds timing features are unique to this Ana-Digi model. I posted the instructions from my CG1123, which is the same as the S25.706C, here: https://tagheuerforums.com/threads/s-el-cg1123-0.136702/post-1898715

Check to see if all your timing features work per the instructions and if so, I'd be less worried. Also, if your movement is still original, it should have a TAG Heuer stamp on it and ETA 251.251 engraved next to the battery. Like this:
However, many of these have had their movements serviced and replaced with an ETA 251.252, which may not have the TAG Heuer stamp. Which doesn't necessarily mean it's a fake, just no longer all original.

Thanks, @Mspeedster. I actually found that page when the watch arrived and can report that the movement functions properly. Although due to my own apparent limitations as a user I must admit it took me a few minutes to figure it out even with the instructions. Will inspect the actual movement as well for the necessary stamps.

You're probably good! 👌

I checked with @Snowy who is another big collector of vintage Heuer/TAG Heuer, someone who shouldn't be easily fooled by a fake. He said his S25.706C is just like yours, no serial number on the case-back cover. He thinks it might have the serial number on the underside of the cover but couldn't check yet. Or maybe as I theorized, TAG didn't use serial numbers in the beginning then decided to add them sometime after initial production started.

@Snowy shared this side by side of his S25.706C next to his CG1123 a few years ago.

^Also, @Snowy's S25.706C bezel appears to be the same style as the later versions and his strap looks to be a newer replacement. But it's not unusual for TAG Heuer to replace scratched up bezels & worn straps when serviced if requested, which could be another explanation for the bezel differences on the early originals.

Great, thanks @Mspeedster. Will also take a look at the underside of the case back.

There's a S25.706C currently for sale on Chrono24, which also doesn't appear to have a serial number on the case back. The listing has a pic of the cover's underside, it doesn't seem to have a serial number there either (although it's not 100% in full view).

The $16K asking price is astronomically high (IMHO), so it better be authentic! 🤯 It comes complete with original box and papers, including a receipt.