Side by side

Sinn 105 St Sa UTCvsSeiko Prospex Sea

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

105 St Sa UTC
Sinn105 St Sa UTC
MSRP $1,998
Prospex Sea
SeikoProspex Sea
MSRP $1,100

At a glance

16 of 29 specs differ
Diameter
105 St Sa UTC41mm
Prospex Sea41.3mm
Power Reserve
105 St Sa UTC38h
Prospex Sea72h
Water Resistance
105 St Sa UTC200m
Prospex Sea300m
MSRP
105 St Sa UTC$1,998
Prospex Sea$1,100

Full specifications

Case

7 specs
Category
Tool
Diver
Diameter
41mm
41.3mm
Thickness
11.9mm
12.5mm
Lug-to-Lug
48.2mm
Finish
bead-blasted
Brushed and polished
Water Resistance
200m
300m
Caseback
Solid

Crystal & Dial

4 specs
Crystal Shape
Flat
AR Coating
Underside
Anti-reflective coating on inner surface
Indices
Applied
Lume
Luminescent
LumiBrite on hands, index(es) and bezel

Movement

4 specs
Caliber
SW 330-2
6R55
Power Reserve
38h
72h
Jewels
25
24
Complications
Date, GMT
None

Pricing

1 specs
MSRP
$1,998
$1,100

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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.

Sinn 105 St Sa UTC

Owners and reviewers widely praise the Sinn 105 St Sa UTC for its legible dial, precise bi-directional bezel action, and the technical, toolish aesthetic of its bead-blasted, TEGIMENT-hardened steel case. The watch is noted for its smooth sweep and snappy date change, with accuracy often within COSC standards, and its vertical day/date display with a German day wheel is a distinctive feature. Some owners find the lug-to-lug distance large for smaller wrists, and the bracelet clasp is considered a weakness by one source, while the non-lumed UTC hand is a deliberate design choice. The Sinn 105 St Sa UTC utilizes a Sellita SW330-1 automatic movement with a 42-hour power reserve and offers 200 meters of water resistance. Overall, the consensus is that owners and reviewers rate the Sinn 105 St Sa UTC highly for its robust build quality and functional tool watch design at its price point.

Seiko Prospex Sea

Seiko Prospex Sea models are widely praised for their excellent build quality, value for money, and comfortable wearability, with many appreciating the vintage-inspired designs and robust construction. Owners note the silicone straps are surprisingly comfortable and well-finished, and the Lumibrite lume is excellent. However, some find the 44.3mm size and thickness too large for smaller wrists, though others report the sizing as perfect. The 6R15 movement in some variants offers accuracy around +4 seconds per day with a 50-hour power reserve, while newer movements offer more. Some models are criticized for a bracelet width not matching the case size or a rudimentary clasp for their price point. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its impressive case work and finishing at its price point.

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