Side by side

Borealis Watch Co. Estoril 300 GMTvsSeiko Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation

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

Estoril 300 GMT
Borealis Watch Co.Estoril 300 GMT
MSRP $600

At a glance

12 of 29 specs differ
Diameter
Estoril 300 GMT41.50mm
Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation39.5mm
Power Reserve
Estoril 300 GMT40h
Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation45h
Water Resistance
Estoril 300 GMT300m
Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation200m
MSRP
Estoril 300 GMT$600
Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation$2,800

Full specifications

Case

5 specs
Diameter
41.50mm
39.5mm
Thickness
13.5mm
12.3mm
Lug-to-Lug
47mm
47.2mm
Lug Width
20mm
20mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
Crystal Shape
Flat
Box
AR Coating
Inner
Anti-reflective coating on inner surface
Lume
BGW9
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Miyota 9075
6L37
Power Reserve
40h
45h
Jewels
25
26

Pricing

1 specs
MSRP
$600
$2,800

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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.

Borealis Watch Co. Estoril 300 GMT

Owners widely praise the Borealis Watch Co. Estoril 300 GMT for its excellent value, robust build quality, and crisp dial, with reviewers highlighting its exceptionally bright BGW9 lume and dive-ready ceramic bezel. Some owners appreciate the brushed and polished finishes, though one owner noted a desire for a white-painted second hand. The included NATO strap is considered too thick with a loose weave, and the sapphire bezel insert is seen by some as a minor aesthetic departure from its inspirations. Overall, owners rate the Borealis Watch Co. Estoril 300 GMT highly for its impressive build quality and value.

Seiko Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation

The Seiko Prospex Marinemaster Marinemaster 1965 Diver’s Modern Re-interpretation is noted for its refined, slimmed-down 39.5mm stainless steel case with a "super hard" coating and a box-shaped sapphire crystal. It offers 200 meters of water resistance and is powered by the slim Caliber 6L37 automatic movement, which has a 46-hour power reserve and an accuracy rating of -10/+15 seconds per day. Reviewers highlight its wearability and functionality as a dive watch, with one noting it as Seiko's thinnest diver ever at 12.3mm. However, concerns are raised about Seiko's continued reliance on the 62MAS design, with one reviewer wishing the Marinemaster remained a separate line, and the bracelet's end-links appearing mismatched in initial images. Its price of A$4,650 is considered high given its specifications compared to competitors.

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