The ETA caliber 2893-X family is part of the Mecaline Specialities line of ETA movements. The 2893 is an automatic movement that is Swiss made with 21 jewels. It is a modular movement that uses the 2892-A2 as a base, but with the addition of a GMT complication. There are three variations of this movement described below.
The 2893 family of movements is available in 3 variations: 2893-1, 2893-2, and 2893-3. The most common of the three is the 2893-2.
All three versions are the same diameter, same jewel count, and the same beat rate. The main differences between these calibers are as follows:
-1 has a world time GMT disc and a quickset date
-2 has a centrally located GMT hand and quickset date at 3:00
-3 has a world time GMT disc and no date
The world time disc on the -1 and -3 features indicators for the different time zones around the globe. Interestingly, despite ETA showing the world time disc as being larger on the -3 without a date, the parts lists calls for the same part number (2520/1) in either the -1 or -3 movements. ETA refers to this GMT disc or 24 hour disc feature as a universal hour mechanism.
Above is part #2520/1 for the universal hour mechanism on the 2893-1 and 2893-3. ETA shows the wheel with the time zone markers, but many brands use a wheel with 24 hour markers instead.