Jack Mason Strat-o-timer GMTvsSeiko 5 Sports Field series

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Measurements

Catalog photos are all shot at the same flattering size. These aren't: every case below shares one millimeter scale.

Jack Mason Strat-o-timer GMT at true scale

Strat-o-timer GMT

Seiko 5 Sports Field series at true scale

5 Sports Field series

Diameter

42mm

39.4mm

Lug-to-Lug

49mm

47.9mm

lowest

Thickness

13.2mm

lowest

13.6mm

Water Resistance

200m

highest

100m

Power Reserve

42h

highest

41h

MSRP

$1,149

$450

lowest

Movement

Miyota 9075

Seiko 4R34

Case

6 specs
Diameter
42mm
39.4mm
Thickness
13.2mm
13.6mm
Lug-to-Lug
49mm
47.9mm
Lug Width
22mm
20mm
Material
316L Stainless Steel
Stainless Steel
Water Resistance
200m
100m

Crystal & Dial

4 specs
Crystal
Sapphire
Hardlex
Crystal Shape
n/a
Curved
Dial Color
n/a
n/a
Lume
None
LumiBrite on hands and index(es)

Movement

3 specs
Caliber
Miyota 9075
Seiko 4R34
Power Reserve
42h
41h
Jewels
0
24

Pricing

1 specs
MSRP
$1,149
$450
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Reviews

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Jack Mason Strat-o-timer GMT

Owners widely praise the Jack Mason Strat-o-timer GMT for its exceptional value and traveler GMT functionality, citing the Miyota 9075 movement and impressive fit and finish, including screw-in bracelet pins, on-the-fly adjustment, sapphire crystal front and back, and a screw-down crown. The 7-link bracelet is frequently highlighted as a standout feature, with one owner calling it the best they have worn. Some reviewers note "chubby" hour markers and a bezel insert that one owner perceived as plastic, though another stated it is sapphire. Overall, owners rate the Jack Mason Strat-o-timer GMT highly for its impressive build quality and traveler GMT complication at its price point.

From video reviewers

The Miyota 9075 true GMT movement is a consensus strength. The lume on the hands, dial, and bezel is also a shared positive feature. Reviewers did not reach a consensus on any weaknesses or points of disagreement.

Seiko 5 Sports Field series

The Seiko 5 Sports Field series is praised for its accessible explorer watch design and decent fit and finish for its price point. Reviewers note the inclusion of a caller GMT complication powered by the 4R34 automatic movement. On balance, owners and reviewers find the Seiko 5 Sports Field series a compelling option for its explorer aesthetic and GMT functionality at an accessible price.

From video reviewers

The prominent five-sided GMT hand enhances legibility and adds a sophisticated aesthetic to the watch. The Seiko 5 Sports Field series offers similar functionality to the Explorer 2 at a lower price, making it a valuable option. Reviewers disagree on whether it's a missed opportunity for Seiko to release this model first, with one reviewer implying it would have been a more logical addition to their lineup.