Formex Reef 42 mmvsSeiko Prospex Sea

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Measurements

Catalog photos are all shot at the same flattering size. These aren't: every case below shares one millimeter scale.

Formex Reef 42 mm at true scale

Reef 42 mm

Seiko Prospex Sea at true scale

Prospex Sea

Diameter

42mm

43.8mm

Lug-to-Lug

47mm

lowest

48.7mm

Thickness

11.4mm

lowest

12.8mm

Water Resistance

300m

highest

200m

Power Reserve

56h

highest

41h

MSRP

$2,414

$625

lowest

Movement

Sellita SW300-1

Seiko 4R35

Case

4 specs
Diameter
42mm
43.8mm
Thickness
11.4mm
12.8mm
Lug-to-Lug
47mm
48.7mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
AR Coating
n/a
Anti-reflective coating on inner surface
Dial Color
Black
n/a
Lume
Super-LumiNova
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW300-1
Seiko 4R35
Power Reserve
56h
41h
Jewels
0
23

Pricing

1 specs
MSRP
$2,414
$625
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Reviews

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Formex Reef 42 mm

Owners widely praise the Formex Reef 42 mm for its comfortable bracelet with a micro-adjust clasp and its overall build and finish, with one owner strongly recommending it. Reviewers highlight its impressive wearability and versatility, noting the COSC-certified Sellita SW300-1 movement and well-finished bracelet. One owner found the lugs' taper hinders third-party strap fit and observed the seconds hand does not perfectly align with markers. On balance, owners and reviewers rate the Formex Reef 42 mm highly for its comfortable bracelet and solid build at its price point.

Seiko Prospex Sea

The Seiko Prospex Sea is widely praised for its excellent value as a sport watch, with owners highlighting its comfortable wearability and generous lume. Reviewers note its solid build quality and attractive design, with some specifically mentioning the matte black dial as a strong point. One owner reports accuracy around +1 to +2 seconds per day. The 43.8mm case size is considered substantial by some, and one owner found the watch heavy and thick, regretting not choosing a different variant. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its blend of classic design and modern utility at an accessible price point.