Side by side

Seiko Prospex Sea 1968 Heritage Diver's GMTvsSpinnaker Dumas Automatic

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

Prospex Sea 1968 Heritage Diver's GMT
SeikoProspex Sea 1968 Heritage Diver's GMT
MSRP $1,500
Dumas Automatic
SpinnakerDumas Automatic
MSRP $239

At a glance

13 of 29 specs differ
Diameter
Prospex Sea 1968 Heritage Diver's GMT42mm
Dumas Automatic44mm
Power Reserve
Prospex Sea 1968 Heritage Diver's GMT72h
Dumas Automatic40h
Water Resistance
Prospex Sea 1968 Heritage Diver's GMT200m
Dumas Automatic300m
MSRP
Prospex Sea 1968 Heritage Diver's GMT$1,500
Dumas Automatic$239

Full specifications

Case

6 specs
Diameter
42mm
44mm
Thickness
12.9mm
15mm
Lug-to-Lug
48.6mm
48mm
Lug Width
20mm
22mm
Material
Stainless Steel
316L Stainless Steel
Water Resistance
200m
300m

Crystal & Dial

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

Movement

3 specs
Caliber
6R54
SII NH35A
Power Reserve
72h
40h
Jewels
24
25

Pricing

1 specs
MSRP
$1,500
$239

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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.

Seiko Prospex Sea 1968 Heritage Diver's GMT

The Seiko Prospex Sea 1968 Heritage Diver's GMT is widely praised for its build quality, finishing, and comfortable wearability, offering good value for its price point. Owners and reviewers highlight the attractive silver/white sunray dial, blue ceramic bezel, and the premium feel of the improved bracelet clasp with excellent micro-adjustment. The Caliber 6R54 movement provides a 72-hour power reserve, and real-world accuracy often exceeds its stated range of +25 to -15 seconds per day, with some owners reporting figures around +3 to +5 seconds per day. However, the caller-style GMT functionality is a point of contention for some, who find the GMT scale difficult to read and prefer a flyer GMT at this price. Some also find the crown position at 4 o'clock undesirable, and a few note a lack of dial contrast or illegibility of the inner bezel.

Spinnaker Dumas Automatic

Owners widely praise the Spinnaker Dumas Automatic for its attractive textured blue dial, applied indices, and well-finished case, noting its comfortable wearability due to a short lug-to-lug distance. Some owners flag the use of mineral crystal instead of sapphire and a bracelet with a learning curve and loose keeper. Overall, owners rate the Spinnaker Dumas Automatic highly for its aesthetics and case finishing at its price point.

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