Guide · 4 min read · Updated November 10, 2026

G-SHOCK Model Numbers Explained: GA-2100-1A1, DW-6900-1V and More

Short answer

A G-SHOCK model number has two parts: the model, such as GA-2100, and a colorway code after it, such as 1A1. The GA-2100-1A is black with gray accents, the GA-2100-1A1 is all black, and the GA-2100-1A2, 1A3 and 1A4 are matte black with neon accents. Every colorway of a model shares the same case, so a bezel made for the GA-2100 fits them all.

How to read a G-SHOCK model number

Take GA-2100-1A1. The first part, GA-2100, is the model: it fixes the case shape, the module and the functions. The part after the second dash, 1A1, is the colorway.

Casio's U.S. site writes the same watch without the first dash, as GA2100-1A1. Both spellings mean the same model.

GA-2100 colorway codes

These are the GA-2100 codes people search for most, as Casio's U.S. site describes them.

GA-2100-1A: black dial with gray accents.
GA-2100-1A1: monochrome black, the all-black CasioAk. Casio's U.S. list price was $110 when we checked.
GA-2100-1A2, GA-2100-1A3 and GA-2100-1A4: three versions of a matte black design with neon accents, listed at $99.
GA-2100-4A: a GA-2100 colorway listed at $110.
GA-2100CM-5A and GA-2100CM-8A: the camouflage series, in beige and in gray.

GA-B2100 and GM-2100: the letters before the number

A letter before the number changes the watch, not just the color. The GA-B2100 adds Tough Solar charging and a smartphone link to the GA-2100 shape; Casio lists it in black (GA-B2100-1A), navy blue (2A) and green (3A). The GM-2100-1A has a silver metal bezel with a black band.

These are different models from the GA-2100, so do not assume a GA-2100 bezel fits them.

DW-6900 and DW-5600 codes

The square and round digital models follow the same pattern.

DW-6900-1V: the standard black DW-6900, listed by Casio in the U.S. at $99.95.
GW-6900-1: the solar atomic model, which Casio describes as based on the original DW-6900.
DW-5600E-1V: the classic black square DW-5600.
DW-5600UE-1 and DW-5600UBB-1: newer versions; Casio describes the DW-5600UBB-1 as the upgrade of the DW-5600BB-1 with an LED backlight.

Longer codes such as GA-2100-1AER

Listings outside the United States often add letters to the end of a code, for example GA-2100-1AER or DW-5600E-1VDF. Casio's U.S. site shows these watches without the added letters, as GA2100-1A and DW5600E-1V.

We could not confirm from Casio what each added letter stands for, so we do not guess. To identify a watch, match the model and the colorway code that Casio's own sites show.

Why the model number matters for a bezel

A bezel follows the case, and the case follows the model. Any GA-2100 colorway takes a GA-2100 bezel, and any DW-6900 colorway takes a DW-6900 bezel. The chart shows the cases we carry bezels for.

G-SHOCK bezel compatibility: models we carry bezels for
G-SHOCK model	Bezel designs	In stock now	Price	Shop
DW-6900	17	15	$59 – $249	DW-6900 bezels
GA-2100	17	17	$149 – $299	GA-2100 bezels
DW-5600	3	3	$200	DW-5600 bezels

Common questions

What is the difference between the GA-2100-1A and the GA-2100-1A1?

They are two colorways of the same watch. The GA-2100-1A has a black dial with gray accents, and the GA-2100-1A1 is monochrome black.

What are the GA-2100-1A2, 1A3 and 1A4?

They are three versions of one GA-2100 design: textured matte black with neon accents. Casio's U.S. site listed each at $99 when we checked.

Is the GA2100-1A1 the same as the GA-2100-1A1?

Yes. Casio's U.S. site writes the model without the first dash. GA2100-1A1 and GA-2100-1A1 are the same watch.

Do all GA-2100 colorways take the same bezel?

Yes. The colorway code changes the colors, not the case, so a bezel made for the GA-2100 fits every GA-2100 colorway. The GA-B2100 and GM-2100 are different models.

What does DW-6900-1V mean?

DW-6900 is the model, the round digital G-SHOCK, and 1V is the colorway code of the standard black version.