Sinn 104 St Sa I W — the white-dial version of Sinn's celebrated 104, widely regarded as one of the best "go anywhere, do anything" watches in German tool-watch horology. Purchased new from WatchBuys (Sinn's authorized US dealer) in March 2021. Selling as a complete set.
Specifications:

Model: Sinn 104 St Sa I W (white dial), ref. 104.012
Case: 41mm polished stainless steel, ~11.5mm thick, 46.5mm lug-to-lug
Lug width: 20mm
Movement: Sellita SW 220-1 automatic, hacking seconds, day-date (English/German switchable)
Crystal: Sapphire front (AR-coated both sides) + sapphire exhibition caseback
Bezel: Bidirectional ratcheting pilot's bezel with lumed triangle
Water resistance: 200m / 20 bar, screw-down crown
Lume: Super-LumiNova
Strap: Sinn very dark brown leather strap with contrast stitching (20mm)
Included: Watch, Sinn inner & outer boxes, Series 104 instruction manual, and warranty card (dated March 2021, WatchBuys).

Condition: Honest pre-owned condition. The watch is running well — a recent timegrapher reading shows approximately -5 seconds/day (photo included), which is excellent and well within factory spec. The white dial, hands, and crystal present cleanly. As with any fully polished case, there is light surface swirling/hairlines on the case and bezel from normal wear. There are a few small nicks on one lug, shown clearly in the photos — please review them before buying.

Shipping: US only. Ships fully insured via USPS Registered Mail with signature required, to your confirmed eBay address only. Please allow extra transit time, as Registered Mail moves through a secure chain-of-custody process and typically takes 5–10 business days. If you add eBay's Authenticity Guarantee at checkout, the watch will instead be routed through eBay's authentication partner for independent inspection before it reaches you.

Returns: No returns accepted. Please review all photos and ask any questions before purchasing — I'm happy to provide additional photos on request.
That said, this watch is eligible for eBay's Authenticity Guarantee, so buyers can have it independently inspected and verified for added peace of mind.