Ok, so I found an interesting post on RWI (thanks to https://forum.replica-watch.info/member/14529-dmuit which is an repair TD on there, if I got it right he is the famous "Domi", a skilled watch tech living in Germany), but it's in the Italian section, so let me put it here for you, as there is a lot of confusion recently on the various Rolex CHS GMT versions around. I'm taking bits here and there from various RWI threads, so I'm not original poster, just trying to put together information for the benefit of the users here. I'll try to expand the thread with what I got from the other versions too (apart the ones in that specific thread) in order to try to create some kind of guide here. 1) the SA3186 (aka VRF3186) VS the SH3186 At this time the SA3186 is mounted in the VRF and V9F rolex and apparently it's the best in class. It has been improved since the 1st SA around, it has a better superficial finishing (especially visible in the more external area of the movement, where there is the stem release pusher respect to the SH ones), it can even take gen balance, like here: Also, it uses the jumping hours module as the old Rolex 3185 which is much more reliable than the new 3186 which has a spring that tends to break and is used inside the SH3186. That's the thing that, when you change the timezone, allows you to change just the hour hand as visible here at 2:01: https://youtu.be/BGlyg7RIsQc?t=121 This is the pic from the SA3186 with the jumping hour sistem exposed: This is a GEN 3185: And this is the system implemented on GEN 3186 and also used in the SH3186: And the broken spring: Anyway, there are around generic (expensive!) date jumper springs: https://www.aliexpress.com/item/32980974691.html   It is not that easy to recognize the SA3186 from the SH3186. By now the only 2 visual differences I managed to find are: - the placement of the screw that fix the hairspring to the hairspring stud - the color/material used for the balance jewel slot, grey on the SH and brass on the SA. This is how it was on the old SA3135 V1 (used back then in the date/time rolexes, NOT A GMT movement):   This  is the new SA3135 V2 and has the same aspect of the SA3186 GMT:   This instead is the SH3135 and has the same aspect of the SH3186 GMT:     Also, the SA3186 is the one available on AliExpress for around 180$ -> https://www.aliexpress.com/item/4000665762877.html As like as the SA3135 V2 NON GMT for around 150$: https://www.aliexpress.com/item/4000666052287.html Also the SH3135 NON GMT is avalable on Ali: https://www.aliexpress.com/item/4000665783923.html   2) the modified CHS 2836  This is probably the more risky of all the CHS movement, it has a history of unrealiability, therefore I'd stay far clear from it. Anyway if you are brave you can always go for it... It is pretty easy to catch it because it has the same autowind system used in the ETA 2836 and clones (this is a picture of a 2824 without the autowind rotor):   And here the same gears on the CHS derived from the 2836:     3) the ICHS 2836  This is the "old style" GMT movement, which is actually the Hanghzhou 6460. It has the "Incorrect hand stack", so the order of the hands is GMT - Hour - Minute - Second. It is a good movement, even if not gen-like. Basically it is a clone of the ETA 2836 with a couple of bits modified to add the GMT function. Nothing bad with it, apart the non gen-like hands order.     So, in the end, which one to go for? I'd personally go for SA3186 and, after that, for the Hangzhou 6460. Eventually for the SH3186 knowing if it breaks it's possible to fix it with a new date jumper spring. Never for the CHS 2836 based.