Bezel: The 1675 bezel is bi-directional and rotates on a spring-based system. There is a flat shaped piece of metal (the tension spring) that sits under the bezel and holds the bezel/insert in place until the user places pressure down on the bezel to rotate. Unlike later models, which incorporate a clicking mechanism, the rotation is smooth. The bezel itself has an outer diameter of ~39.3 mm with two inner rings, the smaller of which is ~34.75 mm and the larger of which is ~35.15mm. There are two types of bezels:
- Early Bezel (left): the grooves span the entire vertical portion of the bezel. These are seen on examples until around 1963.
- Standard Bezel (right): the cut out portions that are not as deep and do not extend into the base of the bezel. These are seen on all examples from 1964 onward.
Insert: Generally, the inserts have an inner diameter of ~30.2 mm, an outer diameter of ~37.75 mm, and are ~0.7 mm thick. They should fit snugly into the bezel with a slight lip of bezel retained above it.
Red/Blue: For the standard Pan-Am or ‘Pepsi’ style bezel, general period correct attributes should include the following:
- red back (not faded, which indicates bleaching)
- flattened top half of the 8’s (these are circular on later blue backed inserts and aftermarket bezels)
- 2’s that do not have an overhanging top (aftermarket ‘hooked’ or ‘overhanging’ 2’s are commonly seen)
- small serifs throughout (with the exception of very fat fonts, which are likely lost with the wearing of the pad)
There are different mentions of what the 12 o’clock triangle (wider triangle, dot in the middle) and coloring (copper tones) should look like for a gilt era insert. These are not steadfast enough to quantify for a reference guide and so I will not be defining which inserts belong to which era. Some things that are more agreed upon are:
- Fuchsia bezel appear to come from the later half of the 1960’s (possibly at the end of the gilt dials, definitely on the early matte dials)
- “Super fat font” bezels (see the fourth picture below) also appear to come from watches in the later half of the 60’s (late gilt and early matte) up to near the 3 million range. Below are some nice examples and some aftermarket ones to compare to. Of note, they are not original to the early/PCG cases.
Black: Black inserts, which can fade to a nice dark blue (and gain the ‘blackberry’ sobriquet), were produced starting around 1976. They have a black back and otherwise hold the same font characteristics as the red / blue bezels above. Some consider these to only be service bezels on the 1675 (available after 1976) but there is not consensus on this point. There is consensus that, when seen on earlier examples, they’ve likely been swapped in. As this is one of the fun parts of GMTs, it’s up to you what you consider to be essential to originality and what look you like.
Blueberry: The originality of these is disputable and I will not be covering them.