Side by side

Marathon Steel Navigator SSNAV-D AutovsFormex Reef 39.5 mm

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

Steel Navigator SSNAV-D Auto
MarathonSteel Navigator SSNAV-D Auto
MSRP $1,400
Reef 39.5 mm
FormexReef 39.5 mm
MSRP $2,230

At a glance

11 of 29 specs differ
Diameter
Steel Navigator SSNAV-D Auto41mm
Reef 39.5 mm39.5mm
Power Reserve
Steel Navigator SSNAV-D Auto40h
Reef 39.5 mm56h
Water Resistance
Steel Navigator SSNAV-D Auto60m
Reef 39.5 mm300m
MSRP
Steel Navigator SSNAV-D Auto$1,400
Reef 39.5 mm$2,230

Full specifications

Case

6 specs
Category
Pilot
Diver
Diameter
41mm
39.5mm
Lug-to-Lug
48mm
45.5mm
Lug Width
20mm
22mm
Material
316L Stainless Steel
Stainless Steel
Water Resistance
60m
300m

Crystal & Dial

2 specs
Dial Color
Black
Bahama Blue
Lume
None
Super-LumiNova

Movement

2 specs
Caliber
Sellita SW220-1
Sellita SW300-1
Power Reserve
40h
56h

Pricing

1 specs
MSRP
$1,400
$2,230

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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.

Marathon Steel Navigator SSNAV-D Auto

The Marathon Steel Navigator SSNAV-D Auto is praised for its durable construction, featuring a sandblasted steel case with improved lugs, a bi-directional bezel with excellent action, and 100m water resistance. Owners appreciate the constant visibility provided by self-illuminating tritium gas tubes and the precision of its ETA F06.412 quartz movement, which offers accuracy to about 10 seconds per year. The watch includes a GMT bezel for dual timekeeping and a synthetic sapphire crystal. Overall, owners and reviewers rate the Marathon Steel Navigator SSNAV-D Auto highly for its robust tool-watch design and reliable tritium illumination.

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.

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