WatchUSeek Watch Forums banner
1 - 5 of 5 Posts

Sinn 857 S UTC
287 Posts
Discussion Starter · #1 · (Edited)
Referencing my initial attempt of fitting the Zuludiver 400 with the twin trigger clasp on my newly purchased Sinn 857 S UTC HERE, entitled “Zuludiver 400 ridiculous work”, I recently switched back to my PVD Tegimeted bracelet.

The job wasn’t so bad the second time around!


Rather than wasting to what I would consider a sneaking into the “expensive” range of of strap price (total price), of around £75 (£50- strap, twin trigger release clasp £25), I decided to stick it on my 2016 reissued SRP775 Turtle, newly coming back from Seiko U.K. service.

I saw this as a super upgrade to my Turtle 🐢 since I stick by an odd rule of trying not to spend over 10% on strap to the watch price.

Having spent more on Hirsh straps for years @watchobession I decided to give @WatchGecko a try as I got more into rubber recently and didn’t want to pay the isofrane prices

I copped the all black to go with my Sinn and having the comfort and found the perfect fit with the strap length, now on the turtle, I thought I’ll pick up an orange version for my new King Turtle SRPE07.

The operations with the additional clasp was not as gruelling to when I had to install the black on my Sinn, now that I know exactly where to cut and which micro adjustment I need.

The Zuludiver twin trigger clasp, which came with 2 springs bars, was actually for the micro adjustment and clasp side, not for the watch lugs side, where I had claim was too large for the rubber holes. In fact, I used the stock clasp of the Zuludiver 400 spring bars to use it on the twin release clasp and those spring bars did not hold. The holes on the twin trigger clasp was too small for the spring bar of the stock clasp.


Stock Zuludiver 400 clasp spring bar


Using the same spring bar on the twin trigger release Zuludiver clasp.

Don't make the same stupid mistake as I did. It costed me an extra strap as I thought the rubber strap was cut too wide so I tried to cut it finer resulting in over cutting my last hole.

The result turned out to be Ok.



I did find a trick that after inserting the Seiko fat spring bar in the lugs end of the strap hole, because it is indeed super tight, before installing it in the watch, twist the rubber with the spring bar out as hard as you can. The rubber needs to spread out over the fat spring bar.

During insertion, it tightened up the end and shortened the rubber ends into almost a triangle shape. Twist the crap out of it back and fourth and if need be, under hot water.

To mimic the stock strap of the King Turle, I actually brought the Zuludiver 285 first and it was only £28, but the chunky design didn’t quite fit the chunky case shape of the new King Turle, which had a even more chunky bezel compare to the original, now I am calling a slim profile to my SRP775.



The feel of the Zuludiver 400 vs the 285 was miles apart IMO. I am not sure if it is because of having the 400 on the clasp, but most certainly, the 400 is much softer and do conform to your wrist better, especially with the clasp vs keeper. Mind you, the keepers stayed where it should be for the 285 very nicely.

Both have the same smell of the goregous Bonetto Cinturini vanilla smell and last for ages.

I have a skin problem, so these vulcanized Italian rubber works for me even over long wear though out the whole day of 24hrs. Its waterproof, non-toxic, hypoallergenic, saltwater and UVA-resistant is what .





Definitely my go to strap configuration for all future turtle. I thought the strap would be a bit thin for the case shape, but the silm profile accentuate the wide turtle case whilst the thickness of the strap hugs the wrist and feels premium.

Even more so than some of the high end straps I have seen from the likes of Sinn & Omege. The only thing is it is not integrated, but due to its thickness, the gap to the case on the lugs is hardly there so for the price point compare to the high end strap, its competely good enough.


Premium Member
39,107 Posts
Nice work. Looks OEM and fits the rest of the watch perfectly.

Enjoy your hard work!

Premium Member
9,803 Posts
Nice! Thanks for walking us through the process — it was quite informative. The end result looks very professional. Enjoy your retrofitted straps.
1 - 5 of 5 Posts