Side by side

Citizen Eco-Drive OnevsFormex Reef GMT

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

Eco-Drive One
CitizenEco-Drive One
MSRP $2,995
Reef GMT
FormexReef GMT
MSRP $2,235

At a glance

12 of 29 specs differ
Diameter
Eco-Drive One36.6mm
Reef GMT42mm
Power Reserve
Eco-Drive One40h
Reef GMT56h
Water Resistance
Eco-Drive One300m
Reef GMT300m
MSRP
Eco-Drive One$2,995
Reef GMT$2,235

Full specifications

Case

5 specs
Category
Dress
GMT
Diameter
36.6mm
42mm
Thickness
12mm
11.4mm
Lug-to-Lug
46mm
47mm
Lug Width
20mm
22mm

Crystal & Dial

3 specs
AR Coating
Underside
Inner
Dial Color
White
Black
Lume
None
Super-LumiNova

Movement

3 specs
Caliber
8845
Sellita SW330-2
Type
Solar
Automatic
Power Reserve
40h
56h

Pricing

1 specs
MSRP
$2,995
$2,235

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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.

Citizen Eco-Drive One

The Citizen Eco-Drive One is widely celebrated for its groundbreaking thinness, with multiple sources confirming its status as the world's thinnest light-powered watch, measuring between 2.98mm and 3.5mm. Owners and reviewers alike praise its exceptional lightness, titanium construction, and good build quality that avoids feeling flimsy, noting its "wow factor" and superb finishing. The watch features a proprietary, ultra-thin Eco-Drive quartz movement and a synthetic sapphire dial, with some models offering up to 12 months of power reserve. However, its high price, ranging from $3,500 to $5,000, is a significant drawback for some, and its aesthetic is considered too plain or dated by a minority who prefer other Citizen models. The Citizen Eco-Drive One is also noted for lacking a seconds hand and having only splash-resistant water protection.

Formex Reef GMT

The Formex Reef GMT is widely praised for its unique porthole case shape, COSC-certified Sellita SW330-2 movement with good finishing, and comfortable quick-release bracelet with on-the-fly micro-adjustment. Reviewers note its robust construction, impressive specifications, and strong value proposition, with a slim 11.4mm profile accommodating 300m water resistance and an exhibition caseback. However, owners widely report the 53mm lug-to-lug span with male endlinks makes it too large for smaller wrists. Some find the bezel action stiff and potentially slippery, and a reviewer desired sharper finishing and edges, deeming the aesthetic too modernist. The GMT variant sacrifices a timing bezel unless swapped, and one owner notes sharp edges on the crown and crown guard. Overall, owners and reviewers highly rate the Formex Reef GMT for its exceptional value and well-executed features, particularly its bracelet system and COSC-certified movement.

From video reviewers

The watch features a COSC-certified SW330-2 GMT movement, which is visible through a sapphire crystal display case back and beautifully decorated. The watch's water-resistance of up to 300m/1000ft is a notable feature. The 42mm diameter may be too large for smaller wrists.

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