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 $625

At a glance

16 of 29 specs differ
Diameter
105 St Sa UTC41mm
Prospex Sea43.8mm
Power Reserve
105 St Sa UTC38h
Prospex Sea41h
Water Resistance
105 St Sa UTC200m
Prospex Sea200m
MSRP
105 St Sa UTC$1,998
Prospex Sea$625

Full specifications

Case

7 specs
Category
Tool
Diver
Diameter
41mm
43.8mm
Thickness
11.9mm
12.8mm
Lug-to-Lug
48.7mm
Lug Width
20mm
22mm
Finish
bead-blasted
Brushed and polished
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
4R35
Power Reserve
38h
41h
Jewels
25
23
Complications
Date, GMT
None

Pricing

1 specs
MSRP
$1,998
$625

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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

The Seiko Prospex Sea is widely praised for its excellent value, solid build quality, and comfortable wearability, with many models featuring impressive lume and attractive dials. Owners and reviewers highlight the modern upgrades on classic designs, such as drilled lugs and reliable movements with hacking and hand-winding capabilities. Some models are noted for their refined case finishing and scratch resistance. Accuracy figures vary, with one owner reporting approximately 4 seconds fast per day, while others find the movements offer good performance for the price. Concerns raised by owners and reviewers include clasps that can feel generic or cheap, and lug widths that some find disproportionate to the case size on certain models. The thickness and weight of some Prospex Sea watches are also noted as substantial. The GMT function on specific models is considered secondary and difficult to read for true travel purposes.

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