Marathon Arctic OSAR 36mm AutomaticvsSeiko 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.

Marathon Arctic OSAR 36mm Automatic at true scale

Arctic OSAR 36mm Automatic

Seiko Prospex Sea at true scale

Prospex Sea

Diameter

36mm

43.8mm

Lug-to-Lug

43.5mm

lowest

48.7mm

Thickness

13mm

12.8mm

lowest

Water Resistance

300m

highest

200m

Power Reserve

n/a

41h

MSRP

$1,200

$625

lowest

Movement

Sellita SW220-1

Seiko 4R35

Case

6 specs
Diameter
36mm
43.8mm
Thickness
13mm
12.8mm
Lug-to-Lug
43.5mm
48.7mm
Lug Width
18mm
22mm
Material
316L Stainless Steel
Stainless Steel
Water Resistance
300m
200m

Crystal & Dial

3 specs
AR Coating
n/a
Anti-reflective coating on inner surface
Dial Color
White
n/a
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW220-1
Seiko 4R35
Power Reserve
0h
41h
Jewels
0
23

Pricing

1 specs
MSRP
$1,200
$625
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Reviews

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

Marathon Arctic OSAR 36mm Automatic

Owners widely praise the Marathon Arctic OSAR 36mm Automatic for its tough, reliable feel and looks, with tritium tubes considered an exotic plus for visibility. The 36mm size is noted as a budget-conscious choice for smaller wrists, fitting well on sub-7-inch wrists, though one owner found the size too small and another is still getting used to it. The watch is described as a purpose-built tool watch, not designed for versatility with suits, but rather for singular focus on usefulness and durability. Overall, owners and reviewers rate the Marathon Arctic OSAR 36mm Automatic highly for its durable tool-watch nature and useful tritium illumination.

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.