Side by side

Formex Reef GMTvsSeestern S450 Ocean Star

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

Reef GMT
FormexReef GMT
MSRP $2,235
S450 Ocean Star
SeesternS450 Ocean Star
MSRP $299
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.

Seestern S450 Ocean Star

Owners widely praise the Seestern S450 Ocean Star's Yachtmaster-style case and flawless bracelet finishing, with one owner noting the ST2130 movement keeps good time. The bezel action is described as having individual notches but feeling like a friction bezel, while another owner flags the bezel and crown action as smooth with perfect alignment. Lume is a point of contention, with one source describing it as a nice cool blue with ice-white application, while others note it as weak or not matching Prospex standards, despite using BGW-9. The watch is considered a "big boy" ideal for larger wrists (19cm+), potentially too large for 17cm wrists due to its size and non-tapering bracelet. Overall, owners rate the Seestern S450 Ocean Star highly for its build quality and finishing at the price point, despite some reservations about its size and lume intensity.

At a glance

15 of 29 specs differ
Diameter
Reef GMT42mm
S450 Ocean Star40mm
Power Reserve
Reef GMT56h
S450 Ocean Star41h
Water Resistance
Reef GMT300m
S450 Ocean Star100m
MSRP
Reef GMT$2,235
S450 Ocean Star$299

Full specifications

Case

7 specs
Category
GMT
Diver
Diameter
42mm
40mm
Thickness
11.4mm
12mm
Lug-to-Lug
47mm
48mm
Lug Width
22mm
20mm
Material
Stainless Steel
316L Stainless Steel
Water Resistance
300m
100m

Crystal & Dial

2 specs
Dial Color
Black
White
Lume
Super-LumiNova
Tritium

Movement

5 specs
Caliber
Sellita SW330-2
TMI NH35A
Beat Rate
28,800 vph
21,600 vph
Power Reserve
56h
41h
Jewels
25
24
Complications
None
GMT, Date

Pricing

1 specs
MSRP
$2,235
$299
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