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GMT-MASTER BEZEL INSERTS FOR THE 1675/16750 AND 16760/16710/16700 MODELS

There are two variations of bezel inserts for the discontinued GMT and GMT II models:

1) Acrylic model inserts (GMT 1675 & GMT 16750)
2) Sapphire model inserts (GMT 16700, GMT II 16760 and GMT II 16710)

The inner and outer diameters are different for both types of inserts. Normally, when measuring an insert, they will not measure exactly to these dimensions due to age, stretch or other factors.

1) Acrylic: 1675/16750
Inner Diameter: 30.2mm...... Outer Diameter: 37.75mm

2) Sapphire: GMT II 16760/16710 GMT 16700:
Inner Diameter: 30.7mm...... Outer Diameter: 37.63mm

If you know the subtle differences between the acrylic and sapphire inserts when viewed from the back, it becomes very apparent whether a GMT insert fits an acrylic or sapphire model.

The sapphire inserts will fit on the 1675/16750 acrylic crystal models – especially if the insert is flattened out a little with the help of a wooden dowel or other item. The bezel will spin freely when installed - even though the inner diameter is slightly less with the sapphire insert than an acrylic insert.

I have placed several photos here depicting the differences between the acrylic inserts (1675/16750) and the sapphire crystal inserts (16760/16710/16700). When viewed from the back, the acrylic inserts have a very thin ring on the outer edge. The sapphire inserts have a thicker outer ring when compared to the acrylic inserts along with a middle ring. When viewed, the sapphire insert appears to have three distinct rings on the back while the acrylic insert appears to have two distinct rings.

In the photos below, I have included a GMT 16750 that has a sapphire insert fit to the bezel and installed on the watch. It fits tight and the bezel turns freely.

AFTERMARKET BEZEL INSERTS

The most common variety of aftermarket GMT bezel inserts have a distinct identifier in one of the numerals. In examining the 2s, if you look closely at the upper top loop of the 2, you will observe that this loop hooks excessively past the base of the 2 which gives the numeral a very distinctive hook which is not like the 2s found on genuine inserts. This type of insert is referred to as the "hooked 2." There are several photos of the "hooked 2" below comparing this aftermarket insert to genuine inserts. One must also be aware that the back side of these aftermarket inserts appear very similar to genuine inserts.

The "hooked 2" inserts can be found for all varieties and colors of the GMT models. From the two-tone brown inserts, gold, black, blue, red/blue, red/black etc., there is a "hooked 2" insert being made.

I have also been made aware of some other variations of aftermarket GMT inserts being sold on ebay. These inserts are often sold by European ebayers and appear very similar to genuine inserts. Personally, I have a problem distinguishing these inserts from genuine GMT inserts. (I do not have any photos here of these inserts.)

BLEACHED BEZEL INSERTS

Artificially or chemically "bleached" inserts are a rather new phenomenon which seems to have gained prominence the past three to four years. They can usually be identified by splotchy colors or uneven fading on the insert. Additionally, from my experience, the back side of the insert is usually overly-faded too, or has splotchy coloring which is indicative of a chemically altered insert.

I have also seen inserts that were chemically altered while the insert remained in the bezel. This type of bleaching is fairly easy to identify when the back side of the insert is examined. Normally, when you examine the back side of a suspected "bleached" insert, and you observe a distinct, darker color around the outer perimeter of the insert, it was probably "bleached" while the insert remained in the bezel. Normally, from the hundreds of inserts that I have seen the past couple of decades, most inserts on the back side retain the vibrance of their original color, regardless of whether the top side of the insert has a naturally, aged color.

Additionally, I have seen inserts from the 1960s that have a nice, faded patina on top but when you examine the back side, it appears to have an uneven or splotchy colors which might lead one to believe where one might believe it was artificially faded. This appearance is quite normal on some of these decades-old inserts and no need for alarm. (I have included a couple photos in this thread depicting a super fat font GMT insert with these attributes.)