Side by side

Formex Reef 39.5 mmvsSeiko Prospex Sea

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
Prospex Sea
SeikoProspex Sea
MSRP $595

At a glance

12 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
Prospex Sea41.7mm
Power Reserve
Reef 39.5 mm56h
Prospex Sea41h
Water Resistance
Reef 39.5 mm300m
Prospex Sea200m
MSRP
Reef 39.5 mm$2,230
Prospex Sea$595

Full specifications

Case

5 specs
Diameter
39.5mm
41.7mm
Thickness
11mm
12.3mm
Lug-to-Lug
45.5mm
49.5mm
Lug Width
22mm
20mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
Crystal
Sapphire
Hardlex
Dial Color
Bahama Blue
Black
Lume
Super-LumiNova
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW300-1
4R35
Power Reserve
56h
41h
Jewels
25
23

Pricing

1 specs
MSRP
$2,230
$595

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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.

Seiko Prospex Sea

Owners and reviewers widely praise the Seiko Prospex Sea for its excellent value, robust build, and superior lume, with many noting its comfortable wearability and faithful design recreations. Some owners report the watch can feel big, thick, and heavy on smaller wrists, while others find the sizing perfect. The bezel action is frequently highlighted as smooth and precise, often exceeding that of less expensive models. On balance, owners and reviewers rate the Seiko Prospex Sea highly for its impressive finishing and value proposition.

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