Side by side

Formex Reef 39.5 mmvsSeiko King Turtle

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
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.

Seiko King Turtle

Owners widely praise the Seiko Prospex Sea for its excellent value, robust build, and superior lume, with many appreciating its faithful recreation of classic designs and proven movements like the 4R36 and 6R15. Reviewers highlight impressive case finishing and durability, noting that even larger models wear smaller than expected due to thoughtful case design. Some owners find the solar quartz models a great entry point, appreciating their design and solar functionality. However, specific variants receive critiques: the bracelet clasp on the Samurai is described as underwhelming, and the Sumo's bracelet width and clasp are seen as too narrow and rudimentary, respectively. The SPB183 is considered expensive for a Japanese watch, and its lume is noted as not quite matching older Seiko Monster models. The GMT function on the SPB519 is deemed less practical for serious travel, and its bezel clicks are described as quieter and mushier.

At a glance

11 of 29 specs differ
Diameter
Reef 39.5 mm39.5mm
King Turtle45mm
Power Reserve
Reef 39.5 mm56h
King Turtle41h
Water Resistance
Reef 39.5 mm300m
King Turtle200m
MSRP
Reef 39.5 mm$2,230
King Turtle$650

Full specifications

Case

4 specs
Diameter
39.5mm
45mm
Thickness
11mm
13.2mm
Lug-to-Lug
45.5mm
47.7mm
Water Resistance
300m
200m

Crystal & Dial

3 specs
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Bahama Blue
Black
Lume
Super-LumiNova
LumiBrite on hands and index(es)

Movement

3 specs
Caliber
Sellita SW300-1
4R36
Power Reserve
56h
41h
Jewels
25
24

Pricing

1 specs
MSRP
$2,230
$650
Keep exploring

More watches worth a look

Matched to the watches above on size, movement, style and price — microbrands first. Open any one to dig in.

Follow this matchup

Get a note when Formex Reef 39.5 mm vs Seiko King Turtle gets more votes, a community discussion, or a price drop. No account needed.

Adjacent matchups

People also compared

Comparisons nearby in the catalog — alternatives to the watches above paired against the matchup.