Side by side

Formex Reef 39.5 mmvsGrand Seiko SBGA427

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
SBGA427
Grand SeikoSBGA427
MSRP $5,800
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 SBGA427

Grand Seiko SBGA427 owners widely praise its extensive Zaratsu polishing and the "hall of mirrors" effect created by its diamond-cut indexes, complemented by a subtle, reeded dial and a striking green seconds hand. The 39mm case is noted for its comfortable, tapered bracelet, and the 9R65 Spring Drive movement is visible through the caseback. Some owners report the highly polished Zaratsu finish is prone to scuffs and scratches, with one mentioning a scratch near 1 o'clock. The Grand Seiko SBGA427 sold for $3750. Overall, owners rate the Grand Seiko SBGA427 highly for its exceptional finishing and the unique visual appeal of its dial and indexes.

At a glance

13 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
SBGA42739mm
Power Reserve
Reef 39.5 mm56h
SBGA42772h
Water Resistance
Reef 39.5 mm300m
SBGA427100m
MSRP
Reef 39.5 mm$2,230
SBGA427$5,800

Full specifications

Case

6 specs
Category
Diver
Dress
Diameter
39.5mm
39mm
Thickness
11mm
12.3mm
Lug-to-Lug
45.5mm
46.8mm
Lug Width
22mm
19mm
Water Resistance
300m
100m

Crystal & Dial

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

Movement

3 specs
Caliber
Sellita SW300-1
9R65
Type
Automatic
Spring Drive
Power Reserve
56h
72h

Pricing

1 specs
MSRP
$2,230
$5,800
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