For sale is a Sinn 556i in excellent condition (no dings, scratches, and crystal is in flawless condition) for $685 which includes shipping within CONUS. Comes on the original Sinn leather strap and boxes/papers. I bought this secondhand from watchuseek member Clarvonn and literally wore it only once. It was originally purchased in December 2014 from Watchbuys. Haven't done a ton of sales on here, but a couple references below:
https://www.watchuseek.com/f63/cwatchman-one-good-guys-2960258.html
https://www.watchuseek.com/f63/cwatchman-excellent-seller-2959026.html
Specs are as follows:
https://www.watchuseek.com/f63/cwatchman-one-good-guys-2960258.html
https://www.watchuseek.com/f63/cwatchman-excellent-seller-2959026.html
Specs are as follows:




- ETA 2824-2
- Self-winding mechanism
- 25 bearing jewels
- 28,800 semi-oscillations per hour
- Seconds stop function
- Shock resistant as per DIN 8308
- Anti-magnetic as per DIN 8309
- Case
- Case made of stainless steel, satinized
- Sapphire crystal glass in front, anti-reflective on both sides
- Transparent case back made of sapphire crystal glass, anti-reflective on the interior
- Case back screw-fastened
- Crown screwable
- Meet the technical requirements for waterproofness, as set out in standard DIN 8310
- Pressure-resistant up to 20 bar
- Low pressure resistant
- Functions
- Hours, minutes, seconds
- Date display
- Dimensions and Weight
- Case diameter: 38,5 mm
- Band lug width: 20 mm
- Case thickness: 11 mm
- Weight without strap: 65 gramme
- Dial and Hands
- Glossy black dial
- Indices coated with luminescent colour
- Hour and minute hand coated with luminescent colour