Squale 1521 Classic COSCvsSeiko 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.

Squale 1521 Classic COSC at true scale

1521 Classic COSC

Seiko Prospex Sea at true scale

Prospex Sea

Diameter

42mm

41.7mm

Lug-to-Lug

48mm

lowest

49.5mm

Thickness

12.5mm

12.3mm

lowest

Water Resistance

500m

highest

200m

Power Reserve

38h

41h

highest

MSRP

$1,965

$595

lowest

Movement

Sellita SW200-1

Seiko 4R35

Case

5 specs
Diameter
42mm
41.7mm
Thickness
12.5mm
12.3mm
Lug-to-Lug
48mm
49.5mm
Material
Steel
Stainless Steel
Water Resistance
500m
200m

Crystal & Dial

5 specs
Crystal
Sapphire
Hardlex
Crystal Shape
Flat
n/a
Dial Color
Black
n/a
Indices
Applied
n/a
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW200-1
Seiko 4R35
Power Reserve
38h
41h
Jewels
0
23

Pricing

1 specs
MSRP
$1,965
$595
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Reviews

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

Squale 1521 Classic COSC

Owners widely praise the Squale 1521 Classic COSC's well-proportioned 42mm case, with one reviewer calling it a masterclass in case design. The COSC certification is noted to improve accuracy, and the bezel indices are now fully lumed, a feature some owners find superior. The brushed case with polished chamfers is described as a significant and attractive aesthetic update. However, some owners prefer older bezel designs, and opinions on the lume are mixed, with one user finding it only "okay." One owner reported moisture ingress after a shower due to a loose case back on a new watch. The Squale 1521 Classic COSC is priced at CHF 1,475 and uses a Sellita SW200-1 movement. Overall, owners rate the Squale 1521 Classic COSC highly for its updated finishing and improved accuracy.

Seiko Prospex Sea

Owners widely report the Seiko Prospex Sea is a well-built watch at a fair price, with some finding its 41.7mm case size perfect while others with smaller wrists consider it big, thick, and heavy. Reviewers consistently praise the excellent lume and robust design. One owner notes the bezel action is smoother and more precise than some other Seiko divers. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its value and proven design.

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