Side by side

Formex Reef 39.5 mmvsGrand Seiko SLGH017

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
SLGH017
Grand SeikoSLGH017
MSRP $10,500

At a glance

12 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
SLGH01740mm
Power Reserve
Reef 39.5 mm56h
SLGH01780h
Water Resistance
Reef 39.5 mm300m
SLGH017100m
MSRP
Reef 39.5 mm$2,230
SLGH017$10,500

Full specifications

Case

6 specs
Category
Diver
Dress
Diameter
39.5mm
40mm
Thickness
11mm
11.7mm
Lug-to-Lug
45.5mm
47mm
Material
Stainless Steel
Titanium
Water Resistance
300m
100m

Crystal & Dial

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

Movement

2 specs
Caliber
Sellita SW300-1
9SA5
Power Reserve
56h
80h

Pricing

1 specs
MSRP
$2,230
$10,500

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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 SLGH017

Grand Seiko SLGH017 owners and reviewers widely praise its impeccable finishing on the applied markers and handset, and its lightweight titanium case and bracelet. The high-beat 9SA5 movement is noted for its approximately 80-hour power reserve, with accuracy figures reported by owners ranging from +4 sec/day to +5 to -3 seconds per day, though some owners express concerns about accuracy deviating significantly from specifications. Some find the "Night Birch" dial stunning and appreciate the Evo 9 case design, while others note the dial texture appears less pronounced on its matte black surface and criticize the handset's proportions and lack of lume. The Grand Seiko SLGH017 is priced at €10,500. On balance, owners and reviewers rate the Grand Seiko SLGH017 highly for its lightweight titanium construction and impeccable finishing.

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