Side by side

Formex Reef 39.5 mmvsGrand Seiko SLGA015

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
SLGA015
Grand SeikoSLGA015
MSRP $12,600
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 SLGA015

The Grand Seiko SLGA015 is widely praised for its exceptional accuracy, with owners reporting performance far exceeding the stated 10 seconds per month. The Spring Drive movement's smooth sweep and 5-day power reserve are also noted strengths, as is the lighter titanium case construction. However, some owners find the bracelet extension non-intuitive, and one noted the clasp scratched easily. The watch features a nature-inspired, wave-like dial texture. Overall, owners rate the Grand Seiko SLGA015 highly for its impressive accuracy and quality construction.

At a glance

13 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
SLGA01543.8mm
Power Reserve
Reef 39.5 mm56h
SLGA015120h
Water Resistance
Reef 39.5 mm300m
SLGA015200m
MSRP
Reef 39.5 mm$2,230
SLGA015$12,600

Full specifications

Case

6 specs
Diameter
39.5mm
43.8mm
Thickness
11mm
13.8mm
Lug-to-Lug
45.5mm
51.5mm
Lug Width
22mm
23mm
Material
Stainless Steel
Titanium
Water Resistance
300m
200m

Crystal & Dial

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

Movement

3 specs
Caliber
Sellita SW300-1
9RA5
Type
Automatic
Spring Drive
Power Reserve
56h
120h

Pricing

1 specs
MSRP
$2,230
$12,600
Keep exploring

More watches worth a look

Matched to the watches above on size, movement, style and price — microbrands first. Open any one to dig in.

Follow this matchup

Get a note when Formex Reef 39.5 mm vs Grand Seiko SLGA015 gets more votes, a community discussion, or a price drop. No account needed.

Adjacent matchups

People also compared

Comparisons nearby in the catalog — alternatives to the watches above paired against the matchup.