Side by side

Fortis Marinemaster M-40vsSeiko Prospex Sea 1968 Heritage Diver's GMT

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
Prospex Sea 1968 Heritage Diver's GMT
SeikoProspex Sea 1968 Heritage Diver's GMT
MSRP $1,500

At a glance

12 of 29 specs differ
Diameter
Marinemaster M-4040mm
Prospex Sea 1968 Heritage Diver's GMT42mm
Power Reserve
Marinemaster M-4038h
Prospex Sea 1968 Heritage Diver's GMT72h
Water Resistance
Marinemaster M-40300m
Prospex Sea 1968 Heritage Diver's GMT200m
MSRP
Marinemaster M-40$3,520
Prospex Sea 1968 Heritage Diver's GMT$1,500

Full specifications

Case

5 specs
Diameter
40mm
42mm
Thickness
13mm
12.9mm
Lug-to-Lug
48.6mm
Lug Width
21mm
20mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Orange
Black
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW220-1
6R54
Power Reserve
38h
72h
Jewels
26
24

Pricing

1 specs
MSRP
$3,520
$1,500

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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 Prospex Sea 1968 Heritage Diver's GMT

The Seiko Prospex Sea 1968 Heritage Diver's GMT is widely praised for its build quality, finishing, and comfortable wearability, offering good value for its price point. Owners and reviewers highlight the attractive silver/white sunray dial, blue ceramic bezel, and the premium feel of the improved bracelet clasp with excellent micro-adjustment. The Caliber 6R54 movement provides a 72-hour power reserve, and real-world accuracy often exceeds its stated range of +25 to -15 seconds per day, with some owners reporting figures around +3 to +5 seconds per day. However, the caller-style GMT functionality is a point of contention for some, who find the GMT scale difficult to read and prefer a flyer GMT at this price. Some also find the crown position at 4 o'clock undesirable, and a few note a lack of dial contrast or illegibility of the inner bezel.

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