Side by side

Casio GBM-2100AvsTimefactors Speedbird GMT

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.

Timefactors Speedbird GMT

Owners widely praise the Timefactors Speedbird GMT for its quality and value, with many appreciating its 36mm case size for wearability and its surprisingly good bracelet. Some owners note the GMT function is on an inner ring, and one owner found the date wheel sunken. The watch is noted for its classic aesthetic and is considered a good value, though purchasing requires patience due to limited order windows. Overall, owners rate the Timefactors Speedbird GMT highly for its wearability and value at the price point.

At a glance

14 of 29 specs differ
Diameter
GBM-2100A44.4mm
Speedbird GMT36mm
Power Reserve
GBM-2100A
Speedbird GMT
Water Resistance
GBM-2100A200m
Speedbird GMT100m
MSRP
GBM-2100A$280
Speedbird GMT$315

Full specifications

Case

8 specs
Category
Sport
Diameter
44.4mm
36mm
Thickness
11.9mm
11.6mm
Lug-to-Lug
49.3mm
42.5mm
Lug Width
18mm
Material
Bio-based Resin / Stainless steel
Stainless Steel
Finish
Water Resistance
200m
100m

Crystal & Dial

4 specs
Crystal
Mineral
Sapphire
AR Coating
No
Dial Color
Silver
Black
Lume
None
Super Luminova X1 C3

Movement

1 specs
Caliber
Ronda 515

Pricing

1 specs
MSRP
$280
$315
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