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Casio watch · analog-digital module

Casio GBA-900 manual and battery (CR2025)

Casio's operation guide for the Casio GBA-900 is the PDF for module 5641: Casio operation guide 5641 (PDF) ↗. It takes a CR2025 battery. The case is 48.9 mm wide, 51.3 mm long (case length L, not lug to lug), and 16.6 mm thick.

Sources checked · How we source numbers
Width (W)
48.9 mm1
Case length (L)
51.3 mm1
not lug to lug
Thickness
16.6 mm1
Lug width
not published by Casio
Casio GBA-900: size drawingCasio GBA-900, cushion case, top and side view to scale: case width 48.9 mm, case length (Casio L) 51.3 mm, lug width — (unknown), thickness 16.6 mm. Bezel, dial and crown size are schematic.lug width —width 48.9case length (Casio L) 51.3TOPthickness 16.6SIDE
Casio GBA-900, top and side, to scaleDrawing from data, not a photo · mm

Module 5641 twins

Casio's manual list puts 5 model codes on this module: same functions, same manual, often the same battery.

Codes of the Casio GBA-900 family[3]GBA-900, GBA-900CB, GBA-900RD, GBA-900SM, GBA-900UU

Casio module 5641: functions, battery and manual

Module: Casio module 5641

The Casio GBA-900 runs on the Casio module 5641, an analog-digital module.

Power source
battery2
Battery life
2 years2
Accuracy
±15 s/month2

Battery

Casio GBA-900 specifications

Case width (W)
48.9 mm1
Lug to lug
not published by Casio; see case length (L)
Case length (L)
51.3 mm1Casio's L of L × W × H, measured differently from lug to lug; we never swap one for the other.
Thickness (H)
16.6 mm1
Lug width
not published by Casio
Weight
61 g1
Crystal
Mineral Glass1
Water resistance
200 m1
Module
Casio module 56413 · analog-digital moduleCasio module 5641 specs
Battery
Accuracy
±15 s/month1
Years made
start not published
Case code
not used by Casio: the module number (module 5641) identifies the watch

On your wrist

The verdict compares the case length (L) with the flat top of your wrist. Balanced from ~18 cm, past the edges below ~16 cm.

= 6.7 in

At the edge on a 17 cm wrist: the 51.3 mm case length (L) covers 94% of an estimated 54.8 mm flat top.

Casio publishes no lug-to-lug for this model, so the verdict uses its case length (L). The strap or bracelet joins inside that length, which makes this a cautious estimate.

Flat top = circumference ÷ 3.1, a community convention, not a measurement of your arm. Compact ≤ 0.75 of the flat top, balanced ≤ 0.89, at the edge ≤ 1. Compare more watches in the watch size calculator.

Casio GBA-900: wrist fitCasio GBA-900 on a wrist, top view to scale. case length (Casio L) 51.3 mm. Wrist 170 mm, estimated flat width 54.8 mm (circumference / 3.1). Ratio 0.94: at the edge.wrist, flat topwrist flat ≈ 54.8case length (Casio L) 51.3At the edge · 51.3 / 54.8 = 0.94estimate: wrist 170 / 3.1 = 54.8 flatcompactbalancededgeoverhang0.750.891
Casio GBA-900 on a 17 cm wristDrawing from data, not a photo · mm

Actual size on your screen

Calibrate once with a bank card and the drawing shows the Casio GBA-900 at 1:1, next to a millimetre ruler.

1:1 · not calibrated: sizes are approximate
Casio GBA-900: size drawingCasio GBA-900, cushion case, top and side view to scale: case width 48.9 mm, case length (Casio L) 51.3 mm, lug width — (unknown), thickness 16.6 mm. Bezel, dial and crown size are schematic.lug width —width 48.9case length (Casio L) 51.3TOPthickness 16.6SIDE
Drawing from data, not a photo · mm
01020304050

Casio GBA-900 strap size

Casio publishes no lug width for the Casio GBA-900. Measure between the lugs with a caliper before buying a third-party strap.

Attachment: not published in our sources.

Find your strap length in the watch strap size tool, with the Casio GBA-900 filled in.

Same size as the Casio GBA-900

The models nearest to the Casio GBA-900 in case width and case length (L), drawn over it to scale; below, every model within 1 mm of its 51.3 mm.

Size comparison: Casio GBA-900, Casio EQB-500, Casio AQ-S810W, Casio AEQ-110WTop-view outlines to scale on one centre. A Casio GBA-900: W 48.9, L 51.3, lug —, T 16.6. B Casio EQB-500: Ø 48.1, L 52, lug —, T 14.1 (vs A: W −0.8 L +0.7 T −2.5). C Casio AQ-S810W: W 48.3, L 52.2, lug —, T 13.7 (vs A: W −0.6 L +0.9 T −2.9). D Casio AEQ-110W: W 48.2, L 52.2, lug —, T 16.7 (vs A: W −0.7 L +0.9 T +0.1).B Ø 48.1D W 48.2C W 48.3A W 48.9A L 51.3B L 52C L 52.2D L 52.2A Casio GBA-900W 48.9 · L 51.3 · lug — · T 16.6B Casio EQB-500Ø 48.1 · L 52 · lug — · T 14.1vs A: W −0.8 L +0.7 T −2.5C Casio AQ-S810WW 48.3 · L 52.2 · lug — · T 13.7vs A: W −0.6 L +0.9 T −2.9D Casio AEQ-110WW 48.2 · L 52.2 · lug — · T 16.7vs A: W −0.7 L +0.9 T +0.1
A Casio GBA-900 and the 3 nearest in size, on one centre, to scaleDrawing from data, not a photo · mm

Nearest in size

  1. ACasio GBA-900this watch
  2. BCasio EQB-500W −0.8 · L +0.7 · T −2.5 mm
  3. CCasio AQ-S810WW −0.6 · L +0.9 · T −2.9 mm
  4. DCasio AEQ-110WW −0.7 · L +0.9 · T +0.1 mm

Differences against A in mm: W case width, L Casio case length, T thickness. Nearest by width and length together, from the published sizes.

Casio GBA-900 questions

Where is the manual for the Casio GBA-900?

The Casio GBA-900 runs Casio module 5641, and Casio publishes the operation guide for that module as a PDF: Casio operation guide 5641. The module number is stamped on the case back. All of the module’s models and its battery are on its page.

How big is the Casio GBA-900?

The Casio GBA-900 measures 48.9 mm wide, 51.3 mm long (Casio's L, not lug to lug), 16.6 mm thick, 61 g.

Will the Casio GBA-900 fit a 7.5-inch wrist?

Balanced: the Casio GBA-900's 51.3 mm case length (L) takes 83% of the ~61.5 mm flat top of a 7.5-inch (19.1 cm) wrist. By the same estimate (circumference ÷ 3.1) it sits balanced from about 18 cm and overhangs the flat top on wrists under about 16 cm.

What battery does the Casio GBA-900 take?

The Casio GBA-900 takes CR2025, rated about 2 years.

What module is in the Casio GBA-900?

The Casio GBA-900 runs on the Casio module 5641, an analog-digital module. Casio's manual list puts 5 model codes on this module, 5 of them GBA-900 codes.

More Casio watches

Sources

Documents checked · Report a wrong number

  1. 1Casio America — GBA900-1A | Black Move Watch - G-SHOCK | CASIO · html · read
  2. 2Casio Computer Co., Ltd. — Operation Guide 5641 (qw5641_EN.pdf) · pdf · read
  3. 3Casio Computer Co., Ltd. — Watch manual search JSON (US locale), manual_search.support.json · json · read