Which is cheaper, the Formex Reef 42 mm or the Seiko Prospex Land Mechanical GMT?

At MSRP the Seiko Prospex Land Mechanical GMT is the cheaper of the two at $1,150, against $2,414 for the Formex Reef 42 mm — a $1,264 gap before any retailer discounting.

Which is bigger, the Formex Reef 42 mm or the Seiko Prospex Land Mechanical GMT?

The Formex Reef 42 mm wears larger at 42mm versus 39.5mm for the Seiko Prospex Land Mechanical GMT — a 2.5mm difference across the dial.

Which has better water resistance, the Formex Reef 42 mm or the Seiko Prospex Land Mechanical GMT?

The Formex Reef 42 mm is rated to 300m versus 20m for the Seiko Prospex Land Mechanical GMT.

Which has a longer power reserve, the Formex Reef 42 mm or the Seiko Prospex Land Mechanical GMT?

The Seiko Prospex Land Mechanical GMT carries a 72-hour power reserve against 56 hours on the Formex Reef 42 mm.

What movement does the Formex Reef 42 mm run compared to the Seiko Prospex Land Mechanical GMT?

Both watches run automatic movements — the Formex Reef 42 mm uses the Sellita SW300-1 and the Seiko Prospex Land Mechanical GMT uses the 6R54.

Side by side

Formex Reef 42 mmvsSeiko Prospex Land Mechanical GMT

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

Formex Reef 42 mm

reef-42mm-automatic-cosc-300m-black

MSRP $2,414

Seiko Prospex Land Mechanical GMT

spb377j1

MSRP $1,150

At a glance

13 of 29 specs differ

Diameter

Reef 42 mm42mm

Prospex Land Mechanical GMT39.5mm

Power Reserve

Reef 42 mm56h

Prospex Land Mechanical GMT72h

Water Resistance

Reef 42 mm300m

Prospex Land Mechanical GMT200m

MSRP

Reef 42 mm$2,414

Prospex Land Mechanical GMT$1,150

Full specifications

Case

6 specs

Crystal & Dial

3 specs

Crystal Shape

Flat

Curved

AR Coating

Inner

Anti-reflective coating on inner surface

Lume

Super-LumiNova

LumiBrite on hands and index(es)

Movement

3 specs

Caliber

Sellita SW300-1

6R54

Power Reserve

56h

72h

Jewels

Pricing

1 specs

MSRP

$2,414

$1,150

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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.

Formex Reef 42 mm

The Formex Reef 42 mm is widely praised for its comfortable bracelet featuring a micro-adjust clasp, COSC-certified Sellita movement, and excellent build quality. Owners appreciate the gradient dial's visual appeal and the overall wearability. Some owners note the seconds hand does not perfectly align with markers, and one owner found the lugs' taper hinders third-party strap fit. The bracelet's length and sporty design are noted as limiting versatility by some. On balance, owners and reviewers rate the Formex Reef 42 mm highly for its impressive wearability and value at the price point.

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Seiko Prospex Land Mechanical GMT

Owners widely praise the Seiko Prospex Land Mechanical GMT for its faithful reconstruction of a classic design, comfortable bracelet, and attractive gray dial with a bubbly crystal. Reviewers highlight its handsome everyday sports watch appeal, solid specifications, and classic Seiko diver aesthetics, offering great value. However, community members are divided on the 6R movement's accuracy, with some reporting significant deviations even after regulation, while others find it competitive for the price. A point of contention is the GMT function, with some wishing for a "flyer" style local jump GMT instead of the "caller" type, and the internal compass bezel is described as finicky and difficult to read. Owners generally consider the Seiko Prospex Land Mechanical GMT overpriced at its retail price, suggesting better value is found on sale or closer to $700.

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