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.

Reef 39.5 mm
FormexReef 39.5 mm
MSRP $2,230
5 Sports SKX series
Seiko5 Sports SKX series
MSRP $495

At a glance

12 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
5 Sports SKX series42.5mm
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$495

Full specifications

Case

5 specs
Category
Diver
GMT
Diameter
39.5mm
42.5mm
Thickness
11mm
13.6mm
Lug-to-Lug
45.5mm
46mm
Water Resistance
300m
100m

Crystal & Dial

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

Movement

3 specs
Caliber
Sellita SW300-1
4R34
Power Reserve
56h
41h
Jewels
25
24

Pricing

1 specs
MSRP
$2,230
$495

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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 as an excellent gateway watch, offering great value with a solid build and powerful lume. Owners widely report that the NH36 movement's accuracy is a "luck of the draw," with official specs allowing up to +/-40 seconds per day, though many experience +/-5 to 10 seconds. Some owners note the lack of a screw-down crown and 100m water resistance, while others highlight its ISO 6425 compliance, 200m water resistance, and screw-down crown as superior tool watch features. Some owners find the original SKX models heavier and bulkier than newer lines, while others praise its iconic, tough, and rugged dive watch design and proven durability. On balance, owners and reviewers rate the Seiko 5 Sports SKX series highly for its iconic, durable dive watch design and strong value proposition.

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