Side by side

Borealis Watch Co. Porto CovovsSeiko Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch

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

Porto Covo
Borealis Watch Co.Porto Covo
MSRP $415

At a glance

12 of 29 specs differ
Diameter
Porto Covo40mm
Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch39.5mm
Power Reserve
Porto Covo40h
Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch45h
Water Resistance
Porto Covo300m
Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch200m
MSRP
Porto Covo$415
Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch$2,800

Full specifications

Case

5 specs
Diameter
40mm
39.5mm
Thickness
11.6mm
12.3mm
Lug-to-Lug
42.5mm
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 9039
6L37
Power Reserve
40h
45h
Jewels
25
26

Pricing

1 specs
MSRP
$415
$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. Porto Covo

The Borealis Porto Covo is widely praised for its 39mm size and unique cantilevered indices that create a 3D effect and depth. Owners note the indices' floating appearance is a well-executed design. One owner reported poor accuracy and a terse customer service response, while another wished for a 42mm size option. The $395 price is considered reasonable for a microbrand, though some feel it does not compare favorably to AliExpress options. Overall, owners appreciate the Borealis Porto Covo for its distinctive dial design and wearable 39mm case size.

Seiko Prospex Marinemaster Marinemaster 1965 Heritage Diver's Watch

The Seiko Prospex Marinemaster 1965 Heritage Diver's Watch is praised for its faithful re-creation of the 62MAS design, with reviewers noting improved wearability due to smaller case sizes (38mm to 40mm) and updated bracelets. Specific models feature a stainless steel case with super-hard coating, ceramic bezel, and a tool-free extension system on the bracelet. Accuracy figures vary, with one model rated at -5/+10 seconds per day and another at -10/+15 seconds per day, powered by movements like the Caliber 8L45 or 6L37 offering 72-hour or 46-hour power reserves respectively. Some reviewers point out drawbacks such as an unsigned winding crown, a lack of tool-free micro-adjust on the clasp for certain models, and a secondary GMT function on one variant. The price point, ranging from $2,800 to $3,600, is considered high by some, especially when compared to other Seiko or Grand Seiko offerings.

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