Side by side

Fortis Marinemaster M-40vsSeiko King Seiko KSK

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

Marinemaster M-40
FortisMarinemaster M-40
MSRP $3,520
King Seiko KSK
SeikoKing Seiko KSK
MSRP $3,300

At a glance

12 of 29 specs differ
Diameter
Marinemaster M-4040mm
King Seiko KSK38.6mm
Power Reserve
Marinemaster M-4038h
King Seiko KSK45h
Water Resistance
Marinemaster M-40300m
King Seiko KSK50m
MSRP
Marinemaster M-40$3,520
King Seiko KSK$3,300

Full specifications

Case

6 specs
Category
Diver
Dress
Diameter
40mm
38.6mm
Thickness
13mm
10.7mm
Lug-to-Lug
45.8mm
Lug Width
21mm
19mm
Water Resistance
300m
50m

Crystal & Dial

3 specs
Crystal Shape
Flat
Box
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Orange
Black

Movement

2 specs
Caliber
Sellita SW220-1
6L35
Power Reserve
38h
45h

Pricing

1 specs
MSRP
$3,520
$3,300

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What people say

Owners + reviewers, side by side

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

Fortis Marinemaster M-40

Owners praise the Fortis Amber Orange for its gorgeous appearance and strong wrist presence, noting its crazy lume and 70-hour power reserve. The Doxa SUB 300T, described as having a superb, eccentric design with a highly legible dial and functional no-decompression bezel, uses an ETA 2824-2 movement. However, the SUB 300T's 42.5mm case wears large and its 14mm thickness is not ideal for dress shirts, though it boasts 1,200m water resistance. On balance, owners appreciate the Fortis Amber Orange for its striking aesthetics and impressive lume.

Seiko King Seiko KSK

Owners and reviewers widely praise the King Seiko KSK for its exceptional dial and case finishing, often compared to higher-end brands, and its slim, retro design. The use of the Calibre 6L35 movement in some variants is seen as a significant upgrade, contributing to a refined feel, while others note the bracelet is unusually nice and the case offers a mix of brushed and polished finishes with sharp angles. However, some owners question the value proposition, citing misaligned screws and clasp components on their examples, and the standard 6R movement in some models is criticized as a disappointment for the price point. Accuracy figures range from +15/-10 seconds per day to +5 to +7 seconds per day, and water resistance is rated at 5 BAR or 50 meters. Overall, owners and reviewers find the King Seiko KSK to be a beautiful and classy watch with fantastic finishing, though some are divided on its value and movement choice at its price point.

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