How to Read Casio & G-SHOCK Model Numbers

Ever looked at a Casio model number like GW-B5600BC-1BER and wondered what on earth it means? You’re not alone. Casio packs a lot of information into those letters and numbers — the watch family, features, color, band type, even which part of the world it was made for. Once you know how to read it, you can tell exactly what a watch is just from its name.

Here’s the full breakdown.

How a Model Number is Built

A Casio model number is read left to right. Each segment tells you something different. Not every model uses all segments — simpler watches may only have a few parts.

Let’s take GW-B5600BC-1BER as an example:

G-SHOCK Prefix Guide

The first letters tell you which G-SHOCK family the watch belongs to and what features it has.

Other Casio Watch Prefixes

Not all Casio watches are G-SHOCKs. These prefixes cover the rest of the lineup.

Series Modifier Letters

These appear between the prefix and the series number. They add a specific feature to the base model.

Example: GA-B2100 — GA (G-Shock Analogue) + B (Bluetooth) + 2100 (series). So it’s a CasiOak with Bluetooth added.

Series Suffix Codes

These come after the series number and before the color code. They describe band type, materials, or special editions.

Band & Material

Special Editions & Collaborations

There are many more special edition suffixes — Casio releases new ones with every collaboration and limited edition.

Color Codes

A single digit tells you the primary color of the band and bezel.

Example: The GA-2100-9A9ER — the 9 tells you the main color is yellow. The A9 after it indicates the accent/secondary color is also yellow — full monochrome.

The Order Letter

After the color digit comes a letter — A, B, C, D, and so on. This distinguishes different variations within the same color. Two watches can both be “black” (color code 1) but look different because of accent colors, display type (positive vs. negative), or other design details.

Sometimes an additional digit follows the order letter, using the same 1-9 color system, to indicate the secondary or accent color.

Example: GA-2100-1A1 — color 1 (black), variant A, accent 1 (black) = all black. GA-2100-1A3 — color 1 (black), variant A, accent 3 (green) = black with green accents.

Region / Market Suffix

The very last letters in a model number tell you which market the watch was intended for. This is important to understand: the watch itself is physically identical regardless of region code. Only the packaging, manual language, and warranty territory differ.

So a GA-2100-1A1ER (Europe) and a GA-2100-1A1DR (Asia) are the exact same watch.

At Time Vibe, our watches carry the ER suffix — European market models with EU warranty.

Let’s Read Some Real Models

Now that you know the system, try reading these from our shop.

GA-2100-1A1ER
GA (G-Shock Analogue) — 2100 (series) — 1 (black) — A1 (variant A, black accent) — ER (Europe)
→ The all-black CasiOak. European model.

GA-B2100-1AER
GA (G-Shock Analogue) — B (Bluetooth) — 2100 (series) — 1 (black) — A (variant A) — ER (Europe)
→ CasiOak with Bluetooth and Tough Solar. European model.

GW-B5600BC-1BER
GW (WaveCeptor — solar + atomic) — B (Bluetooth) — 5600 (series) — BC (band/bezel variant) — 1 (black) — B (variant B) — ER (Europe)
→ A square G-SHOCK with solar, atomic timekeeping, Bluetooth, and a composite band. European model.

GM-2110D-3AER
GM (Metal-Covered) — 2110 (series) — D (steel bracelet) — 3 (green) — A (variant A) — ER (Europe)
→ Metal bezel CasiOak on a stainless steel bracelet, green dial. European model.

GWG-B1000-1AER
GWG (Mudmaster) — B (Bluetooth) — 1000 (series) — 1 (black) — A (variant A) — ER (Europe)
→ Mudmaster with solar, atomic, Bluetooth, triple sensor. The ultimate outdoor G-SHOCK.