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
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

The Seiko Prospex Sea is widely praised for its excellent value, solid build quality, and comfortable wearability, with many models featuring impressive lume and attractive dials. Owners and reviewers highlight the modern upgrades on classic designs, such as drilled lugs and reliable movements with hacking and hand-winding capabilities. Some models are noted for their refined case finishing and scratch resistance. Accuracy figures vary, with one owner reporting approximately 4 seconds fast per day, while others find the movements offer good performance for the price. Concerns raised by owners and reviewers include clasps that can feel generic or cheap, and lug widths that some find disproportionate to the case size on certain models. The thickness and weight of some Prospex Sea watches are also noted as substantial. The GMT function on specific models is considered secondary and difficult to read for true travel purposes.

At a glance

11 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
Prospex Sea43.8mm
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$625

Full specifications

Case

4 specs
Diameter
39.5mm
43.8mm
Thickness
11mm
12.8mm
Lug-to-Lug
45.5mm
48.7mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
AR Coating
Inner
Anti-reflective coating on inner surface
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
$625
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