Side by side

Seestern S450 Ocean StarvsYema Skin Diver CMM.20

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

S450 Ocean Star
SeesternS450 Ocean Star
MSRP $299
Skin Diver CMM.20
YemaSkin Diver CMM.20
MSRP $2,372

At a glance

13 of 29 specs differ
Diameter
S450 Ocean Star40mm
Skin Diver CMM.2039.5mm
Power Reserve
S450 Ocean Star41h
Skin Diver CMM.2040h
Water Resistance
S450 Ocean Star100m
Skin Diver CMM.20200m
MSRP
S450 Ocean Star$299
Skin Diver CMM.20$2,372

Full specifications

Case

4 specs
Diameter
40mm
39.5mm
Thickness
12mm
11.5mm
Lug-to-Lug
48mm
47mm
Water Resistance
100m
200m

Crystal & Dial

3 specs
Crystal
Sapphire
Domed Sapphire
Dial Color
White
Black
Lume
Tritium
None

Movement

5 specs
Caliber
TMI NH35A
Yema CMM.20
Beat Rate
21,600 vph
28,800 vph
Power Reserve
41h
40h
Jewels
24
25
Complications
GMT, Date
None

Pricing

1 specs
MSRP
$299
$2,372

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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.

Seestern S450 Ocean Star

Owners widely praise the Seestern S450 Ocean Star's Yachtmaster-style case and flawless bracelet finishing, with one owner noting the ST2130 movement keeps good time. The bezel action is described as having individual notches but feeling like a friction bezel, while another owner flags the bezel and crown action as smooth with perfect alignment. Lume is a point of contention, with one source describing it as a nice cool blue with ice-white application, while others note it as weak or not matching Prospex standards, despite using BGW-9. The watch is considered a "big boy" ideal for larger wrists (19cm+), potentially too large for 17cm wrists due to its size and non-tapering bracelet. Overall, owners rate the Seestern S450 Ocean Star highly for its build quality and finishing at the price point, despite some reservations about its size and lume intensity.

Yema Skin Diver CMM.20

Owners and reviewers widely praise the Yema Skin Diver CMM.20 for its vintage aesthetic, 39mm-39.5mm case size, and the in-house CMM.20 micro-rotor movement. The watch features a textured cream dial, sharp applied indices, and a satisfyingly over-engineered push-to-turn bi-directional bezel. The fully brushed bracelet with toolless micro-adjust clasp is highlighted as a significant improvement, though some note its extended lug-to-lug may challenge smaller wrists. Accuracy figures range from -3/+7 seconds per day to erratic results between 0 and -10 seconds per day, with a 70-hour power reserve. Some owners express concerns about the brand's QC reputation and the micro-rotor movement's performance, while one reviewer noted questionable finishing on a prototype's hour hand and a rattly clasp. Overall, owners and reviewers rate the Yema Skin Diver CMM.20 highly for its vintage styling and improved bracelet at the price.

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