Specifications
- Reference
- SY23S400
- Family
- Sistem51
- Category
- Classic
- Status
- Current
- Case material
- Stainless steel
- Case diameter
- 42 mm
- Case thickness
- 13.8 mm Official
- Lug-to-lug
- 50.6 mm Official
- Lug width
- —
- Water resistance
- 30 m
- Bezel
- —
- Calibre
- SISTEM51 Official
- Power reserve
- 90 h
Official product page · retrieved October 21, 2026
Does it fit your wrist?
Enter your wrist circumference. The watch appears to scale on the flat top of the wrist.
Comfortable
Lug-to-lug 50.6 mm on a flat top of 54.1 mm: 94 % of the width.
Lug-to-lug is 75 to 95% of the flat top, the usual comfortable range.
Measurements and sources
Brands rarely publish thickness, lug width and lug-to-lug together. Each observation below is kept separate, with who gave it.
Case thickness
| Value | Type | Source | Date |
|---|---|---|---|
| 13.8 mm | Official | Swatch | October 21, 2026 |
Lug-to-lug
| Value | Type | Source | Date |
|---|---|---|---|
| 50.6 mm | Official | Swatch | October 21, 2026 |
Lug width
Lug width is the gap between the lugs, where the strap fits. It is not lug-to-lug.
No source gave this figure yet.
Calibre source
Official Swatch · retrieved October 21, 2026
Other versions in the same case
These references differ only by dial, bracelet or bezel colour. The brand gives them the same case dimensions, so the figures on this page apply to them too.
Other Swatch models
| Watch | Ø | Thickness | Lug-to-lug | Calibre |
|---|---|---|---|---|
| Skin 42 mm SS07B115 | 42 mm | 6.7 mm | 45.6 mm | — |
| New Gent 41 mm SO29Z150 | 41 mm | 9.85 mm | 47.4 mm | — |
| Skin Irony 38 mm SYXG101 | 38 mm | 5.8 mm | 45.6 mm | — |
| Big Bold 47 mm SB02B104 | 47 mm | 14 mm | 52.5 mm | — |
| Irony 25 mm YSS300G | 25 mm | 8 mm | 28.7 mm | — |
| Gent 34 mm GE718 | 34 mm | 8.75 mm | 39.2 mm | — |
Show 4 more
| Watch | Ø | Thickness | Lug-to-lug | Calibre |
|---|---|---|---|---|
| Bioceramic MoonSwatch SO33M100 | 42 mm | 13.25 mm | 47.3 mm | — |
| MoonSwatch SO33M106 | 42 mm | 13.25 mm | 47.8 mm | — |
| Irony Chrono 43 mm YVB416 | 43 mm | 12.67 mm | 49 mm | — |
| Bioceramic Scuba Fifty Fathoms SO35B400 | 42.3 mm | 14.4 mm | 48 mm | SISTEM51 |