Side by side

Formex Reef 39.5 mmvsGrand Seiko SLGB023

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

Reef 39.5 mm
FormexReef 39.5 mm
MSRP $2,230
SLGB023
Grand SeikoSLGB023
MSRP $12,400

At a glance

12 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
SLGB02340.8mm
Power Reserve
Reef 39.5 mm56h
SLGB02372h
Water Resistance
Reef 39.5 mm300m
SLGB023300m
MSRP
Reef 39.5 mm$2,230
SLGB023$12,400

Full specifications

Case

5 specs
Diameter
39.5mm
40.8mm
Thickness
11mm
12.9mm
Lug-to-Lug
45.5mm
48.5mm
Lug Width
22mm
21mm
Material
Stainless Steel
Titanium

Crystal & Dial

3 specs
AR Coating
Inner
Yes
Dial Color
Bahama Blue
Black
Lume
Super-LumiNova
None

Movement

3 specs
Caliber
Sellita SW300-1
9RB1
Type
Automatic
Spring Drive
Power Reserve
56h
72h

Pricing

1 specs
MSRP
$2,230
$12,400

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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.

Formex Reef 39.5 mm

The Formex Reef 39.5 mm is widely praised for its refined finishing, comfortable and well-proportioned case design, and impressive specifications for its price point, including COSC-certified Sellita SW300-1 movement and 300m water resistance. Owners and reviewers highlight the tool-less micro-adjust clasp and quick-release spring bars as practical features. Some reviewers note that the 22mm lug width feels slightly disproportionate to the smaller case, and the bracelet could benefit from more taper, though this is a point of contention for some owners who value the overall package. A prototype crown protrusion issue is noted as being addressed for production. On balance, owners and reviewers rate the Formex Reef 39.5 mm highly for its excellent value and well-executed design.

Grand Seiko SLGB023

Owners and reviewers widely praise the Grand Seiko SLGB023 for its comfortable 40.8mm titanium case and the smooth winding feel of its Spring Drive 9RB1 movement. The dial's gradient blue "ushio" motif is a highlight, though some reviewers note the bezel's fully lumed scale as a missed opportunity. Enthusiasts are divided on the power reserve indicator's placement and the design of the hour and minute hands. Overall, owners and reviewers rate the Grand Seiko SLGB023 highly for its comfortable titanium case and the refined Spring Drive movement.

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