Side by side

Formex Reef 42 mmvsSeiko Prospex Sea 1968 Heritage Diver's GMT

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

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.

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.

At a glance

10 of 29 specs differ
Diameter
Reef 42 mm42mm
Prospex Sea 1968 Heritage Diver's GMT42mm
Power Reserve
Reef 42 mm56h
Prospex Sea 1968 Heritage Diver's GMT72h
Water Resistance
Reef 42 mm300m
Prospex Sea 1968 Heritage Diver's GMT200m
MSRP
Reef 42 mm$2,414
Prospex Sea 1968 Heritage Diver's GMT$1,500

Full specifications

Case

4 specs
Thickness
11.4mm
12.9mm
Lug-to-Lug
47mm
48.6mm
Lug Width
22mm
20mm
Water Resistance
300m
200m

Crystal & Dial

2 specs
AR Coating
Inner
Anti-reflective coating on inner surface
Lume
Super-LumiNova
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
Sellita SW300-1
6R54
Power Reserve
56h
72h
Jewels
25
24

Pricing

1 specs
MSRP
$2,414
$1,500
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