Side by side

Bremont Supermarine 300MvsGrand Seiko SBGA427

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

Supermarine 300M
BremontSupermarine 300M
MSRP $3,550
SBGA427
Grand SeikoSBGA427
MSRP $5,800

At a glance

13 of 29 specs differ
Diameter
Supermarine 300M40mm
SBGA42739mm
Power Reserve
Supermarine 300M40h
SBGA42772h
Water Resistance
Supermarine 300M300m
SBGA427100m
MSRP
Supermarine 300M$3,550
SBGA427$5,800

Full specifications

Case

7 specs
Category
Diver
Dress
Diameter
40mm
39mm
Thickness
12mm
12.3mm
Lug-to-Lug
46.8mm
Lug Width
20mm
19mm
Material
904L Stainless Steel
Stainless Steel
Water Resistance
300m
100m

Crystal & Dial

2 specs
AR Coating
Inner
Yes
Dial Color
Green
Black

Movement

3 specs
Caliber
BE-92AE
9R65
Type
Automatic
Spring Drive
Power Reserve
40h
72h

Pricing

1 specs
MSRP
$3,550
$5,800

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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.

Grand Seiko SBGA427

Grand Seiko SBGA427 owners widely praise its extensive Zaratsu polishing and the "hall of mirrors" effect created by its diamond-cut indexes, complemented by a subtle, reeded dial and a striking green seconds hand. The 39mm case is noted for its comfortable, tapered bracelet, and the 9R65 Spring Drive movement is visible through the caseback. Some owners report the highly polished Zaratsu finish is prone to scuffs and scratches, with one mentioning a scratch near 1 o'clock. The Grand Seiko SBGA427 sold for $3750. Overall, owners rate the Grand Seiko SBGA427 highly for its exceptional finishing and the unique visual appeal of its dial and indexes.

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