Guide · 3 min read · Updated
How to Find Your G-SHOCK Model and Module Number
Short answer
Turn the watch over: the model name and a four-digit module number in a box are engraved on the steel case back. The model name, such as GA-2100 or DW-5600, tells you which bezels and straps fit. The module number, such as 5611, identifies the movement inside and the operation guide Casio publishes for it.
Where is the model number on a G-SHOCK?
It is on the back of the watch. The steel case back is engraved with the model name, for example GA-2100, and a four-digit number inside a rectangle, for example 5611. The number in the rectangle is the module number.
Model number and module number: what is the difference?
The model name describes the whole watch: its case shape, materials and colorway. The module number describes the movement inside, the part that keeps time and runs the display.
One module can be used in several models. The resin GA-2100 and the steel-bezel GM-2100 both use module 5611, for example. One model can also change module over the years: the DW-6900 has used module 3230 and, since 2023, module 3529.
What each number is for
You need the model name for parts and the module number for instructions.
- Bezels and straps: buy by the model name, because parts follow the case shape.
- Setting the time and using the functions: use the operation guide for your module number.
- Battery type and battery life: these depend on the module.
What if the case back is worn?
The model name is also printed on the hang tag and the box the watch came in, and on the receipt or order confirmation. If none of those survive, send us clear photos of the front and back and we will tell you which of our bezels, if any, fits.
Common questions
What is a G-SHOCK module number?
It is the four-digit number in a box on the case back. It identifies the movement inside the watch and the operation guide Casio publishes for it.
What G-SHOCK model do I have?
Read the model name engraved on the case back, next to the boxed module number. For example, a CasioAk reads GA-2100 with module 5611.
Can two G-SHOCK models share a module?
Yes. The GA-2100 and the GM-2100 both use module 5611, so they are set the same way even though their cases differ.
Do I need the module number to buy a bezel?
No. Bezels follow the case, so the model name is what matters. The module number helps when two versions of a model exist.