Side by side

Formex Reef GMTvsSeiko Astron

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

Reef GMT
FormexReef GMT
MSRP $2,235
Astron
SeikoAstron
MSRP $2,500

At a glance

12 of 29 specs differ
Diameter
Reef GMT42mm
Astron42mm
Power Reserve
Reef GMT56h
Astron40h
Water Resistance
Reef GMT300m
Astron100m
MSRP
Reef GMT$2,235
Astron$2,500

Full specifications

Case

5 specs
Thickness
11.4mm
12.4mm
Lug-to-Lug
47mm
49.5mm
Lug Width
22mm
14mm
Material
Stainless Steel
Titanium
Water Resistance
300m
100m

Crystal & Dial

2 specs
AR Coating
Inner
Super-clear coating
Lume
Super-LumiNova
LumiBrite on hands and index(es)

Movement

4 specs
Caliber
Sellita SW330-2
5X83
Type
Automatic
Quartz
Power Reserve
56h
40h
Jewels
25
14

Pricing

1 specs
MSRP
$2,235
$2,500

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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 GMT

The Formex Reef GMT is widely praised for its unique porthole case shape, COSC-certified Sellita SW330-2 movement with good finishing, and comfortable quick-release bracelet with on-the-fly micro-adjustment. Reviewers note its robust construction, impressive specifications, and strong value proposition, with a slim 11.4mm profile accommodating 300m water resistance and an exhibition caseback. However, owners widely report the 53mm lug-to-lug span with male endlinks makes it too large for smaller wrists. Some find the bezel action stiff and potentially slippery, and a reviewer desired sharper finishing and edges, deeming the aesthetic too modernist. The GMT variant sacrifices a timing bezel unless swapped, and one owner notes sharp edges on the crown and crown guard. Overall, owners and reviewers highly rate the Formex Reef GMT for its exceptional value and well-executed features, particularly its bracelet system and COSC-certified movement.

From video reviewers

The watch features a COSC-certified SW330-2 GMT movement, which is visible through a sapphire crystal display case back and beautifully decorated. The watch's water-resistance of up to 300m/1000ft is a notable feature. The 42mm diameter may be too large for smaller wrists.

Seiko Astron

Owners widely praise the Seiko Astron for its spectacular technology, solar-powered quartz movement, and GPS time synchronization, making it a convenient grab-and-go option. The watch is frequently noted for its comfortable and lightweight titanium build, with some models featuring well-finished cases and robust ceramic bezels. Reviewers and owners alike highlight the dial's dynamic and shiny appearance, with textured hour markers and high-contrast edges. Accuracy is generally considered good, with figures ranging from +/- 15 seconds per month to within 1/2 second per day, easily corrected by GPS signal. However, some owners note that DST requires manual adjustment and that automatic time syncing depends on proximity to radio wave towers. The price point is a concern for some, who feel it competes with luxury watches without the same aesthetic appeal. One owner pointed out minimal lume and a slight misalignment of the minute hand on their model.

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