The Tool Desk
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What is the difference between the Sinn 105 St Sa and 105 St Sa UTC?
The main choice is between a calendar-focused display and a second-time-zone display. The standard 105 St Sa has day and date indications and a multifunction bezel with minute markings and a 12-hour scale. The 105 St Sa UTC replaces the day display with an orange UTC hand and a bidirectional, ratcheting 24-hour bezel.
| Model | Additional display | Bezel function | Dial options |
|---|---|---|---|
| 105 St Sa | Day and date | Minute timing and 12-hour second-time-zone scale | Matte black or white |
| 105 St Sa UTC | UTC hand for a second time zone | Bidirectional 24-hour ratcheting bezel | Matte black or white |
These model and dial options are listed in Sinn’s 2025–2026 catalog. The UTC product sheet describes the orange arrow hand and 24-hour bezel on the UTC version.
How does the Sinn 105 UTC bezel work?
The UTC model gives you two ways to show another time zone. Sinn’s October 2020 product sheet says: “Using the bidirectional rotating bezel with 24-hour ratcheting, you can set up a second time zone.”
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Use the bezel to shift the second-time-zone reading
Read the orange UTC hand against the bezel’s 24-hour scale. Rotating the bezel changes the displayed second-time-zone offset without resetting the orange hand. This lets you adjust the second-time-zone reading at the bezel while leaving the hand’s setting untouched.
Set the UTC hand conventionally
You can also set the orange UTC hand with the crown, then read it against the fixed 24-hour scale. Sinn’s product sheet documents both approaches; choose the bezel adjustment when you want to change the displayed offset without moving the hand.
The standard 105 St Sa’s 12-hour bezel serves a different purpose: it can track a second time zone on a 12-hour scale, but it is not the UTC model’s 24-hour hand-and-bezel arrangement.
Case, crystal and water resistance
Sinn’s 2025–2026 catalog lists a 41 mm stainless-steel case, sapphire crystals on both sides, 20-bar water resistance and low-pressure resistance for the series. The UTC product sheet also specifies these core case and resistance features for the UTC variants.
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For fit, Hodinkee’s November 2020 launch report gives the series dimensions as 11.9 mm thick, 47.4 mm lug-to-lug and 20 mm lug width. Those are launch-era reported figures; Sinn’s newer catalog excerpt confirms the 41 mm diameter but does not restate all of those dimensions. Hodinkee also reported a weight of 73 g without a strap.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Movement and power reserve: check the exact reference
Hodinkee’s 2020 launch coverage identifies the Sellita SW 220-1 in the day/date models and the SW 330-1 in the UTC models, with launch-reported power reserves of 38 and 42 hours respectively. Sinn’s UTC product sheet confirms the SW 330-1 for the UTC model. Treat the day/date movement and reserve as launch-report information rather than assuming they apply to every current reference; verify the specification for the exact watch you are considering.
Which Sinn 105 should you choose?
- Choose the 105 St Sa if day and date are the useful complication and a 12-hour second-time-zone bezel is sufficient.
- Choose the 105 St Sa UTC if you want a dedicated 24-hour UTC hand and a bezel that can adjust the displayed second-time-zone offset.
- Then choose the dial and mount. Both models are listed with matte black or white dials. Compare the supplied strap or bracelet on the exact reference, and confirm strap attachment and compatibility before buying a separate 20 mm strap.
Sinn’s catalog lists two-year guarantee coverage. Check current manufacturer or seller terms for the region and reference you plan to buy; the catalog listing alone does not establish the terms currently applicable to every market.
Availability and launch pricing
The catalog establishes black- and white-dial versions in the 2025–2026 lineup, but its cited excerpt does not provide current prices. For context only, Hodinkee reported 2020 U.S. launch prices of $1,560–$1,840 for the day/date models and $1,830–$2,110 for the UTC models, varying by mount. These historical launch figures should not be read as current prices.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
