cazalea[Seiko Moderator]
20873
Grande GMT explained
The Grande GMT has one movement and two faces. Each face has multiple sub-dials.
THE FRONT
The front face has a silver/white dial with main time indicated by blued hands. A day/night indicator is at 2, with small seconds at 4:30 and crown-adjusted big date display at 7.
THE BACKThe rear face is black with luminous hands. The main dial indicates time in your second time zone. At 1:30 is an 8-day power reserve indicator. At 5 is a day/night indicator for your second time zone. At 7 is the indicator which shows where you are in hours east or west of GMT. On the photo below I am at midnight GMT time. It's neither east nor west, and the 24-hour subdial says it's midnight.
One downside of this watch is the back never gets any light to power up the luminous material unless you wear it a long time with this side up...

Pushers on either side of the crown allow you to step the second time zone hands forward or back one hour at a time. A single push on the bottom moves the time to 11 pm; one zone west of GMT

A second push makes it 10; two zones west of GMT

My watch has a custom strap; the normal strap is brown crocodile.

If you ponder for awhile you will come up with a dilemma - how does the watch know where your home time is, and whether it's east or west of GMT? You adjust the hours of offset using a tiny pusher on the "side" of the watch case

I really like this watch (along with the other Reversos that we share)

I swapped a Grande Date which has this window through which you can see the movement,

and the power reserve on the front, but I like the additional complexity of the Grande GMT.
Cheers,
Cazalea