Side by side

Bremont Supermarine 300MvsSeiko Prospex Sea

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

Supermarine 300M
BremontSupermarine 300M
MSRP $3,550
Prospex Sea
SeikoProspex Sea
MSRP $1,500

At a glance

13 of 29 specs differ
Diameter
Supermarine 300M40mm
Prospex Sea43.5mm
Power Reserve
Supermarine 300M40h
Prospex Sea70h
Water Resistance
Supermarine 300M300m
Prospex Sea200m
MSRP
Supermarine 300M$3,550
Prospex Sea$1,500

Full specifications

Case

6 specs
Diameter
40mm
43.5mm
Thickness
12mm
13.3mm
Lug-to-Lug
51mm
Lug Width
20mm
22mm
Material
904L Stainless Steel
Titanium
Water Resistance
300m
200m

Crystal & Dial

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

Movement

3 specs
Caliber
BE-92AE
6R35
Power Reserve
40h
70h
Jewels
25
24

Pricing

1 specs
MSRP
$3,550
$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.

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

Seiko Prospex Sea owners and reviewers praise its Marinemaster-style aesthetic, excellent case finishing, and impressive LumiBrite lume. The watch is powered by the 6R15 movement with a 50-hour power reserve and comes with both a steel bracelet and a silicone strap. Some owners find the Seiko Prospex Sea to be a great value and a suitable first "proper" watch, while others report it is uncomfortably big, thick, and heavy on smaller wrists. Reviewers note the GMT function is secondary with a less prominent scale, and the bezel's quieter clicks may not appeal to all. On balance, owners and reviewers rate the Seiko Prospex Sea highly for its classic design and finishing at its price point.

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