Side by side

Bremont ionBirdvsSeestern S450 Ocean Star

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

ionBird
BremontionBird
MSRP $5,800
S450 Ocean Star
SeesternS450 Ocean Star
MSRP $299

At a glance

15 of 29 specs differ
Diameter
ionBird43mm
S450 Ocean Star40mm
Power Reserve
ionBird40h
S450 Ocean Star41h
Water Resistance
ionBird
S450 Ocean Star100m
MSRP
ionBird$5,800
S450 Ocean Star$299

Full specifications

Case

7 specs
Category
Pilot
Diver
Diameter
43mm
40mm
Thickness
12mm
Lug-to-Lug
48mm
Lug Width
20mm
Material
Titanium
316L Stainless Steel
Water Resistance
100m

Crystal & Dial

2 specs
Dial Color
Regular length (15cm - 19cm wrist size)
White
Lume
None
Tritium

Movement

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

Pricing

1 specs
MSRP
$5,800
$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.

Bremont ionBird

Owners report the Bremont ionBird is overpriced and features a printed dial with a poorly placed date window at 4:30, which some find visually disruptive. However, some owners suggest its case finishing is superior to competitors. The 43mm titanium Bremont ionBird GMT is powered by a COSC-certified BE-93-2AV automatic movement and retails for $5,795. On balance, owners and reviewers find the Bremont ionBird's date window placement and price point to be significant drawbacks.

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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