Side by side

Formex Reef 39.5 mmvsSinn U18

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

Reef 39.5 mm
FormexReef 39.5 mm
MSRP $2,230
U18
SinnU18
MSRP $3,488
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 39.5 mm

The Formex Reef 39.5 mm is widely praised for its refined finishing, comfortable and well-proportioned case design, and impressive specifications for its price point, including COSC-certified Sellita SW300-1 movement and 300m water resistance. Owners and reviewers highlight the tool-less micro-adjust clasp and quick-release spring bars as practical features. Some reviewers note that the 22mm lug width feels slightly disproportionate to the smaller case, and the bracelet could benefit from more taper, though this is a point of contention for some owners who value the overall package. A prototype crown protrusion issue is noted as being addressed for production. On balance, owners and reviewers rate the Formex Reef 39.5 mm highly for its excellent value and well-executed design.

Sinn U18

The Sinn U18 is praised for its unique deep blue/green dial with three-dimensional oxygen bubbles that change with light, and its comfortable, easily adjustable bracelet. Owners find the watch stunning and a piece of history, appreciating the refined hands. The Sinn U18 features a 44mm, 15.5mm thick case made from German submarine steel, offering a 2000-meter dive specification and Sinn's Ar-Dehumidifying technology, powered by a Sellita SW300-1 movement. The case thickness is apparent, and the watch comes as a complete set with box and papers for $3,000-$3,680. On balance, owners and reviewers rate the Sinn U18 highly for its striking dial and robust build.

At a glance

14 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
U1844mm
Power Reserve
Reef 39.5 mm56h
U1842h
Water Resistance
Reef 39.5 mm300m
U182,000m
MSRP
Reef 39.5 mm$2,230
U18$3,488

Full specifications

Case

7 specs
Diameter
39.5mm
44mm
Thickness
11mm
15.5mm
Lug-to-Lug
45.5mm
Material
Stainless Steel
high-strength
Finish
Brushed and polished
Water Resistance
300m
2000m
Caseback
Solid

Crystal & Dial

5 specs
Crystal Shape
Flat
AR Coating
Inner
Dial Color
Bahama Blue
Black
Indices
Applied
Lume
Super-LumiNova
None

Movement

1 specs
Power Reserve
56h
42h

Pricing

1 specs
MSRP
$2,230
$3,488
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