Side by side

Casio GBM-2100AvsCitizen Series 8 831

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Casio GBM-2100A

The premium stainless steel bezel and Bluetooth connectivity are highlighted strengths. The increased mass from the metal bezel is noted as a potential drawback for some wearers. Reviewers differ on its value proposition compared to other G-Shock models.

Citizen Series 8 831

Owners widely praise the Citizen Series 8 831 for its finishing, with one owner noting it exceeded expectations. Reviewers highlight the textured Ice Blue dial and the bracelet's play of light, contributing to a comfortable and luxurious feel on the wrist. The watch features a 40mm ion-plated stainless steel case, a sapphire crystal, and 100 meters of water resistance. It is powered by the in-house Miyota Caliber 9051 automatic movement, which has a 42-hour power reserve and an accuracy range of -10 to +20 seconds per day. On balance, owners and reviewers rate the Citizen Series 8 831 highly for its impressive finishing and dial design at its price point.

From video reviewers

The case finishing, with its contrasting brushed and polished surfaces, is a notable strength. The 40mm case size and comfortable fit are also consistently mentioned. Reviewers did not reach a consensus on any weaknesses.

At a glance

14 of 29 specs differ
Diameter
GBM-2100A44.4mm
Series 8 83140mm
Power Reserve
GBM-2100A
Series 8 83142h
Water Resistance
GBM-2100A200m
Series 8 831100m
MSRP
GBM-2100A$280
Series 8 831$1,095

Full specifications

Case

7 specs
Diameter
44.4mm
40mm
Thickness
11.9mm
0mm
Lug-to-Lug
49.3mm
0mm
Lug Width
20mm
Material
Bio-based Resin / Stainless steel
Stainless Steel
Finish
Water Resistance
200m
100m

Crystal & Dial

3 specs
Crystal
Mineral
Sapphire
AR Coating
No
Underside
Dial Color
Silver
Green

Movement

3 specs
Caliber
Miyota 9051
Type
Quartz
Automatic
Power Reserve
42h

Pricing

1 specs
MSRP
$280
$1,095
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