Seiko Prospex SeavsSquale 1521 Classic COSC

lug2lug doesn't sell watches. Buy links open the brand's or seller's own site. Some links are affiliate links: lug2lug may earn a commission at no extra cost to you. Disclosures

Measurements

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

Seiko Prospex Sea at true scale

Prospex Sea

Squale 1521 Classic COSC at true scale

1521 Classic COSC

Diameter

41mm

42mm

Lug-to-Lug

46.9mm

lowest

48mm

Thickness

12.3mm

lowest

12.5mm

Water Resistance

200m

500m

highest

Power Reserve

70h

highest

38h

MSRP

$900

lowest

$1,965

Movement

Seiko 6R35

Sellita SW200-1

Case

5 specs
Diameter
41mm
42mm
Thickness
12.3mm
12.5mm
Lug-to-Lug
46.9mm
48mm
Material
Stainless Steel
Steel
Water Resistance
200m
500m

Crystal & Dial

5 specs
Crystal Shape
Curved
Flat
AR Coating
Anti-reflective coating on inner surface
n/a
Dial Color
n/a
Black
Indices
n/a
Applied
Lume
LumiBrite on hands, index(es) and bezel
None

Movement

3 specs
Caliber
Seiko 6R35
Sellita SW200-1
Power Reserve
70h
38h
Jewels
24
0

Pricing

1 specs
MSRP
$900
$1,965
Keep your wishlist and collection together in the appExplore the app

Reviews

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

Seiko Prospex Sea

Owners widely praise the Seiko Prospex Sea for its value and robust build, with many highlighting its excellent lume and attractive design. Some owners find the 41mm case size perfect, while others with smaller wrists consider it too large, thick, and heavy. The stock rubber strap is noted as uncomfortable for land wear by one owner. Overall, owners rate the Seiko Prospex Sea highly for its design and value at the price point.

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.

Similar watches

Matched to the watches above on size, movement, style and price, microbrands first. Open any one to dig in.

DiscussionNot started

Also compared

Comparisons nearby in the catalog: alternatives to the watches above paired against the matchup.