Side by side

Serica Ref. 5303 Diving ChronometervsSeestern S450 Ocean Star

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

Ref. 5303 Diving Chronometer
SericaRef. 5303 Diving Chronometer
MSRP $1,768
S450 Ocean Star
SeesternS450 Ocean Star
MSRP $299

At a glance

14 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
S450 Ocean Star40mm
Power Reserve
Ref. 5303 Diving Chronometer42h
S450 Ocean Star41h
Water Resistance
Ref. 5303 Diving Chronometer300m
S450 Ocean Star100m
MSRP
Ref. 5303 Diving Chronometer$1,768
S450 Ocean Star$299

Full specifications

Case

5 specs
Diameter
39mm
40mm
Thickness
12.2mm
12mm
Lug-to-Lug
46.5mm
48mm
Material
Stainless Steel
316L Stainless Steel
Water Resistance
300m
100m

Crystal & Dial

3 specs
AR Coating
Yes
Inner
Dial Color
Enamel Black
White
Lume
Super-LumiNova
Tritium

Movement

5 specs
Caliber
M100 COSC
TMI NH35A
Beat Rate
28,800 vph
21,600 vph
Power Reserve
42h
41h
Jewels
25
24
Complications
COSC
GMT, Date

Pricing

1 specs
MSRP
$1,768
$299

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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.

Serica Ref. 5303 Diving Chronometer

Owners widely praise the Serica Ref. 5303 Diving Chronometer for its excellent wearability, definitive style, and smooth, confident bezel action. The dual scale on the bezel is noted as surprisingly useful, and the crown action, winding, and hacking are reported to work perfectly. One owner describes the Serica 5303-3 as gorgeous and unique, though another notes the crown can appear comically large. On balance, owners rate the Serica Ref. 5303 Diving Chronometer highly for its blend of unique design and robust functionality.

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.

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