Side by side

Casio GBM-2100AvsPhoibos Reef Master

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

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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.

Phoibos Reef Master

Owners widely praise the Phoibos Reef Master for its exceptional value, highlighting its sapphire crystal, DLC coating, and extensive BGW9 lume. The watch is noted for its cool lume, with one owner finding it not bulky despite its robust build. The Shamrock Green dial and texture are highly praised, as is the comfortable bracelet with solid end links. However, the bezel action is described as rough, and the basic folding clasp is a disappointment. Accuracy is reported as excellent, with one owner seeing +-2 sec/day. Some find the 42mm size almost too big for their wrists, and the date window is considered too small. Overall, owners rate the Phoibos Reef Master highly for its impressive feature set and value at its price point.

From video reviewers

The Reef Master offers excellent value for its price point. Reviewers noted concerns regarding the bracelet quality.

At a glance

15 of 29 specs differ
Diameter
GBM-2100A44.4mm
Reef Master42mm
Power Reserve
GBM-2100A
Reef Master
Water Resistance
GBM-2100A200m
Reef Master200m
MSRP
GBM-2100A$280
Reef Master$335

Full specifications

Case

7 specs
Category
Sport
Diver
Diameter
44.4mm
42mm
Thickness
11.9mm
13mm
Lug-to-Lug
49.3mm
48mm
Lug Width
22mm
Material
Bio-based Resin / Stainless steel
Stainless Steel
Finish

Crystal & Dial

4 specs
Crystal
Mineral
Sapphire
AR Coating
No
Yes
Dial Color
Silver
Green
Lume
None
Super-LumiNova

Movement

3 specs
Caliber
Seiko NH38
Type
Quartz
Automatic
Power Reserve
0h

Pricing

1 specs
MSRP
$280
$335
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