Side by side

Formex Reef 39.5 mmvsSeiko 5 Sports SKX series

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

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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 5 Sports SKX series

The Seiko 5 Sports SKX series is widely praised for its value, robust build, and powerful lume, with owners appreciating its comfortable bracelets and improved movement featuring hacking and hand-winding. Some owners find the original SKX models heavy and bulky, while others praise their ruggedness and iconic dive watch design. Reviewers note the 38mm models offer great value at around €350 and are exemplary gateway watches, though their 100m water resistance without a screw-down crown makes them unsuitable for diving. The Seiko 5 Sports SKX series is seen as a decent watch, especially under £200, but lacks the tool watch capabilities of the original SKX, missing a screw-down crown, bezel pip, and ISO rating. On balance, owners and reviewers rate the Seiko 5 Sports SKX series well for its blend of value, improved movement, and tool-watch aesthetic, despite some missing dive certifications.

At a glance

12 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
5 Sports SKX series38mm
Power Reserve
Reef 39.5 mm56h
5 Sports SKX series41h
Water Resistance
Reef 39.5 mm300m
5 Sports SKX series100m
MSRP
Reef 39.5 mm$2,230
5 Sports SKX series$350

Full specifications

Case

5 specs
Diameter
39.5mm
38mm
Thickness
11mm
12.1mm
Lug-to-Lug
45.5mm
44.2mm
Lug Width
22mm
20mm
Water Resistance
300m
100m

Crystal & Dial

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

Movement

3 specs
Caliber
Sellita SW300-1
Seiko 4R36
Power Reserve
56h
41h
Jewels
0
24

Pricing

1 specs
MSRP
$2,230
$350
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