The reference 16710 was in production from 1989 to 2007, making it a relatively long 18-year manufacturing period. During this time, there were some changes within this reference, resulting in modifications to the GMT Master 16710 that are now considered distinct variants. The initial dials of the GMT 16710 featured Tritium markers and were produced until around 1997/1998. These watches had the inscription "SWISS - T<25" at 6 o'clock. From 1998/1999 onwards, Tritium was replaced with Luminova luminescent material, and the dials bore the inscription "SWISS" at 6 o'clock. These are known as the "Swiss-only" dials. During a very brief transitional period (probably less than 6 months), Rolex used the "SWISS T<25" dials with Luminova luminescence.