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.

Reef 42 mm

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 specsCrystal & Dial
3 specsMovement
3 specsPricing
1 specsReviews
Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.
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.
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.
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