Rolex GMT Master 16700 & 16710 cheat sheet

Basic Information

NameRolex GMT MasterRolex GMT Master II
Reference1670016710
Movement31753185
Diameter40mm40mm
Thickness11,8mm12,4
Lug to lug47,5mm47,5
Lug width20mm20mm
MaterialSteelSteel
Water Resistance100m100m
Basic information

The two watches are very similar, but they have a few key differences. The movement of 16710 is more advanced and allows user to move hour & GMT hand independently. The 16700 works like any other watch, except GMT hand completes a single revolution in 24h timespan.

In addition to the functional differences due to the movement, there are other differences. 16700 was never offered with a SEL bracelet, and its manufacturing stopped at 2000 and 16710 came with two movements.

Features

Feature1670016710
BezelOnly Pepsi / BlackBlack, Pepsi and Coke
TritiumBefore 1998Before 1998
Swiss only/Luminova1998-19991998-1999
Super luminovaNeverAfter 1999
Lug holes AlwaysBefore 2000
Solid end-link braceletNeverAfter 2000
Cal 3186 movementNeverVery late in production
Rolex GMT Master 16700 with SEL bracelet.

Personal Preference

For me, despite the fact that I own a 16700, the best combination is 2001-2003 GMT Master II because:

  • Superluminova
  • SEL bracelet
  • Lug holes

Sinn 156 and Sinn 156b

ManufacturerSinn
Reference156b
MovementLemania 5100
Diameter43mm
Thickness15mm
Lug to lug51mm
Lug width20mm
MaterialStainless Steel
Water Resistance10bar
Service price600€-700€
Basic information

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.

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.

Serviceability

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.

Variations

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.

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.

FeatureReference
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.

Conclusion

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.

Omega Planet Ocean cal. 2500, 42mm

Overview

Omega Planet Ocean (PO) line was introduced in 2005. The watches come in both 45mm and 42mm size and are famous for being worn by Special Agent James Bond played by Daniel Craig. In Casino Royale, Daniel Craig wore the 45mm planet ocean on rubber strap and in Quantum of Solace the 42mm 2201.50 on steel bracelet.

ManufacturerOmega
Reference2201.50
Movement2500 (ETA 2892-A2)
Diameter42mm
Thickness14,5mm
Lug to lug48mm
Lug width20mm
MaterialStainless Steel
Water Resistance600m
Basic information

The design of the PO draws from the history of the Omega Seamaster. The PO has a two part bezel found in pre-bond Seamasters and some of the earlier Omega references. The source of the bezel design is most likely Omega Seamaster 300 ref CK2913 produced in late 1950s. Another historic design choice is the curved lugs, which omega have been using since the appearance of first ST Speedmasters.

Various References

One thing worth mentioning is that the cal 2500 Planet Ocean has sharper case than the 2531.80 or 2254.50 Seamasters. While the lugs on the 2254.50 are similar, the form is considerably softer than on the Planet Ocean. This creates an impression of quality of the finish and a more modern look. I haven’t handled a modern unpolished Speedmaster myself, but it is said that modern Speedmasters have similar quality to the lugs.

It may be that all of the 2531.80s and 2254.50s that I have handled have been polished, but at this point, it would be extremely bad luck. Until otherwise proves, I’m going to assume that the edges on the older SM300 lyre lugs weren’t as sharp as on the PO lyre lugs.

Because of the many different color combinations, strap options and sizes, the following table attempts to summarise the reference numbers for 42mm Planet Oceans:

ReferenceStrapBezel colorIndex Color
2201.50BraceletBlackWhite
2901.50.91Stiched RubberBlackWhite
2901.50.81RubberBlackWhite
2201.51BraceletBlackOrange
2201.52MeshBlackOrange
2901.51.82Rubber (orange stitches)BlackOrange
2209.50BraceletOrangeOrange
2909.50.91RubberOrangeOrange
2909.50.38LeatherOrangeOrange
42mm Planet Ocean References

The sheer number of available references may make finding the right watch to purchase difficult. However, it is a good idea to extend one’s searches as deals can be had in any of the references. Unfortunately sometimes dodgy sellers downplay the size and offer 45mm references as 42mm and this creates further confusion.

Bracelet vs Strap

As outlined earlier, the PO came in at least four different strap configurations: steel bracelet, steel mesh, stitched rubber and rubber. I have had pleasure to handle the non-sticthed rubber, and it is easily one of the best rubber straps I have had. It is both comfortable, doesn’t have the groce vanilla smell, which connoisseurs of poverty-grade rubber straps claim to be characteristic of nice vulcanised rubber. The strap doesn’t cause itch even when worn extensively.

The bracelet for the cal 2500 Omegas is 1580 / 952. Unfortunately, my watch never came with bracelet, so until I can source one second hand, I’m unable to review it. I know that the bracelet came with both pins and screws. As with 2254.50, a popular modification is to add micro adjustment clasp to the bracelet. More of this including the parts numbers can be found in the 2254.50 article.

ReferenceComment
1580/952Original steel bracelet
1589/858Steel bracelet from cal 8500
98000144Rubber strap
98000364Rubber strap from cal 8500
Available bracelets for cal 2500

The 1589/858 sits slightly too thick on the watch, but many prefer it because of availability and better clasp. The incorrect size of the 858 end link is especially noticeable where lyre lug meets the end-link itself. The rubber strap 98000364 also extends slightly above the lugs, but it is barely noticeable.

In addition to the steel bracelet and the rubber straps, the cal 2500 Planet Ocean wears well on a shark mesh. This is one of my personal favourites because the mesh is light and comfortable. The part number for the sharkproof mesh is 020ST1380237.

Hand Winding

The hand-winding experience of the cal 2500c is very nice and smooth. Unlike the 1120 or the Rolex Calibers, you can only hear a very faint sound of turning gears when hand-winding. In many watches, I would associate this winding to the wrong direction. Once wound full, just like the 1120, the movement gives nice pleasurable clicks to tell the winder to do something more productive with their life.

2500c vs 2500d

Anyone who is looking to buy any cal 2500 Omega watch is bound to find a lot of discussion over the differences of the movement. The differences have been discussed extensively. In short, the 2500d comes with three-tier escapement as opposed to the two-tier escapement of the 2500c. It is said online that the advantage of this is that the service interval of the 2500d is longer and the 2500d movement is less subject to failure due to wear or dislocation of the part.

Conclusion

The biggest misconception regarding the Planet Ocean 42mm is that it is a big watch. This is most likely caused by its 45mm cousin, or the newer 43,5mm versions. The 42mm PO wears slightly smaller than the flatter 2254.50 despite being taller. It also wears considerably smaller than Seiko MM300, which feels like a chunk of steel strapped to your wrist. On my 16,5cm wrist, the watch feels perfectly balanced on the rubber strap.

The various PO strap options, the two different movement types and the three different bezels/dials configurations can make the purchase confusing and somewhat difficult. Beyond the various references, the watch has a lot to offer: not many watches are simultaneously conservative (2201.50), playful (2201.51) and slightly obnoxious (2209.51).

Omega Seamaster Professional 300m 2254.50

Overview

This is a review about the Omega Seamaster 300 2254.50. The watch was sold along the ‘Bond’ Seamaster 2531.80 and its differences to the 2531.80 are sword hands, indices, bracelet, colors and big triangle dial. The “big triangle” on the dial along with the rectangular indices are a throwback to the classic 166.024 and 165.024 Seamasters.

ManufacturerOmega
Reference2254.50
Movement1120
Diameter42mm
Thickness11,7mm
Lug to lug47mm
Lug width20mm
MaterialStainless Steel
Water Resistance300m
Basic information

The distinctive features of the 2254.50 are its thinness, sword hands and speedmaster style bracelet with slight taper to the clasp.

However, to keep Omega references complex, Omega released a few other similar, but different models, such as the 2255.80 electric blue and steel, 2533.50 America’s cup with black dial and steel and the 2054.50 which nearly identical to the 2254.50, but mounted on the 5-link Bond bracelet.

Year ProductionReference NumberAppearance
19932531.80Round indices, skeleton hands, both in tritium and luminova. Black dial, blue bezel, 5-link bracelet.
19972254.50Big triangle, painted rectangular indices, sword hands. Black dial, black bezel, speedmaster bracelet.
19972054.50Big triangle, painted rectangular indices, sword hands. Black dial, black bezel, 5-link bracelet.
2255.80Big triangle, painted rectangular indices, sword hands. Blue dial, steel bezel, speedmaster bracelet.
2533.50Big triangle, applied rectangular indices, sword hands, America’s Cup printed on dial. Black dial, steel bezel, 5-link bracelet.
Table of automatic SMP300 references

Hand-winding Experience

The Omega cal 1120 derived from ETA 2824-2 is a workhorse and can be enjoyed for its utilitarian aspects. It is neither pretty or advanced, but it does the job. The advantage of the movement is that most watchmakers are able to service it.

The hand-winding experience of the 2254.50 is close to standard ETA 2824-2. There is really nothing new to anyone who has handled an ETA 2824-2. While the winding experience is quite far away from modern in-house luxury watch movements, the watch gives satisfiable clicks to notify when it has been fully wound. It also keeps excellent time.

Nato Strap

The 1610/930 bracelet of the 2254.50, even with its modest taper, is not for everyone. For a person with a smaller wrist, it can fear bulky and cumbersome. For those whose wrists swell a lot, the bracelet can be uncomfortable as it lacks micro-adjustment. The 2254.50 is a relatively thin watch and compared to the watch head the bracelet can feel big and unbalanced. Those familiar with 5-digit Rolex watches may even hate the bracelet. Luckily, not all is lost, because the 2254.50 is only 11mm thick it wears perfect on a nato strap.

Because the watch is thin, it is possible to use some of the thicker Nato straps. Similarly Nato straps with keepers, won’t feel too thick. The waffle weave Blushark Orca is a good example. Even with a 1,5mm thick waffle weave Orca, the 2254.50 is at 14mm of thickness. This is still 1,5mm thinner than a cal 8500 Planet Ocean.

My preference is to wear it on a Nato strap over the excellent Speedmaster-style bracelet. Luckily, most watches come with the bracelet, so you can decide for yourself and you won’t miss out.

Modifications

ModPart number
Non-America’s Cup Dial064WZ3121001
Planet Ocean Second Hand066WZ4315
Micro adjustable claspClasp: 117STZ001154 (large)
Clasp: 117STZ004666 (small)
Sadle-link (2x): 0118ST1589
Pins (2x): 0128ST0166
Screws (4x): 0124ST3307
Mods and part numbers

Non-America’s Cup Dial: In this mod, the dial of the 2254.50 is changed to the Non-America’s Cup Dial. In this dial the indices and Omega text are applied vs painted and printed.

Planet Ocean Seconds Hand: In this mod the second hand is changed to PO seconds hand which some think fits better the sword hands. Also the tip of the seconds hand is brighter.

Micro-adjustable clasp: In this mod the normal clasp is changed to the more modern micro-adjustable clasp. This requires changing the last links to ones with screw ends. This gives the wearer three different positions to adjust the watch thorough the day.

Serviceability

While the movement service for the 2254.50 should be cheap, the bezel is expensive to replace. This is because the bezel will come with the whole bezel assembly instead of just insert. If one is looking for a 2254.50, it is best to find an example with excellent bezel.

The case of the 2254.50 is softer than more modern planet oceans and speedmasters. The big issue here is that the Omega lyre lugs take polishing particularly bad. A watch that has undergone improper polish is impossible to repair without a new case, so it is best to ensure that the edges of the lyre lugs are sharp.

Conclusion

The 2254.50 is a great watch. The bracelet and the bezel action of the 2254.50 is a letdown. The size, sword hands, lume and dial make up for its downfalls. People who suffer from swollen hands should definitely look into the micro-adjustment mod. The watch is simply great and works well with bracelet and even better on a Nato strap.

Pros

  • Size
  • Serviceability
  • Sword hands
  • Lume

Cons

  • Bracelet is heavy and tapers only slightly. Micro adjustment is minimal and depends on half-links.
  • Bezel action

The most notable characteristic of this watch are its thinness and sword hands. People who prefer wrist presence are going to enjoy the more modern Seamasters or Planet Oceans. Either way, so far this is the only modern watch in the Seamaster line up with the sword hands, which makes it favourite to some watch collectors.