Side by side

Bremont Supermarine 300MvsSeiko Prospex Sea 1965 Heritage Diver's Watch

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

Supermarine 300M
BremontSupermarine 300M
MSRP $3,550

At a glance

11 of 29 specs differ
Diameter
Supermarine 300M40mm
Prospex Sea 1965 Heritage Diver's Watch40mm
Power Reserve
Supermarine 300M40h
Prospex Sea 1965 Heritage Diver's Watch72h
Water Resistance
Supermarine 300M300m
Prospex Sea 1965 Heritage Diver's Watch300m
MSRP
Supermarine 300M$3,550
Prospex Sea 1965 Heritage Diver's Watch$1,300

Full specifications

Case

3 specs
Thickness
12mm
13mm
Lug-to-Lug
46.4mm
Material
904L Stainless Steel
Stainless Steel

Crystal & Dial

4 specs
Crystal Shape
Flat
Curved
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Green
Black
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
BE-92AE
6R55
Power Reserve
40h
72h
Jewels
25
24

Pricing

1 specs
MSRP
$3,550
$1,300

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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.

Bremont Supermarine 300M

The Bremont Supermarine 300M is praised for its comfortable 40mm and 42mm case sizes, with owners noting the 42mm wears well on smaller wrists due to its lug design. One owner highlights the 13mm thinness of the 40mm case, considered compact for a 300m diver. The watch is priced at $1375. On balance, owners and reviewers appreciate the Bremont Supermarine 300M for its wearability and compact dimensions, especially for a dive watch.

Seiko Prospex Sea 1965 Heritage Diver's Watch

The Seiko Prospex Sea 1965 Heritage Diver's Watch is praised for its refined engineering and updated features, including a 300m water resistance and a 72-hour power reserve from the Caliber 6R55 movement in a 40mm case. Owners note its better build quality and interesting finishing with a mix of polished and brushed surfaces. The "Tranquil Teal" variant features a jewel-toned dial with a rippling-water pattern. However, some owners consider the price too high, and concerns exist regarding the accuracy of the 6R movements, with some reporting theirs run slow. One review notes a reflective dial that impacts legibility. On balance, owners and reviewers appreciate the Seiko Prospex Sea 1965 Heritage Diver's Watch for its refined design and improved specifications over previous generations, despite some reservations about movement accuracy and price.

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