Swatch Irony Sistem51 YIS431
The steel-cased Sistem51: a 51-part Swiss automatic with a 90-hour power reserve, no hacking and no hand-winding, 42 mm, 30 m water resistance, polymer strap. The least expensive Swiss-made automatic in our catalog.
In stock · sold by Amazon.com. Price as of November 3, 2026, 18:15 UTC.
What you get
Published manufacturer specifications. Fields we could not verify are left out rather than guessed.
How the 41 spec points add up
Value Score = 100 × √(spec points per dollar ÷ the best ratio among automatic sport watches in stock on Amazon today). Full methodology.
Compared with other automatic sport watches
Same type, other model families, verified Amazon prices today. See the full Automatic Sport & Everyday Watches ranking →
| # | Watch | Movement | Crystal | Water res. | Case diameter × lug-to-lug | Fits wrist | Spec pts | Price | Value Score | Buy |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | Automatic (4R36) | Hardlex | 100 m | 42.5 × 46 mm | ≥ 16.6 cm (6.5″) | 68 | $280.00third-party | 100 | Amazon |
| 2 |  | Automatic (4R36) | Hardlex | 100 m | 40 × 44.6 mm | ≥ 16.1 cm (6.3″) | 68 | $306.00third-party | 96 | Amazon |
| 3 |  | Automatic (8210) | Mineral | 50 m | 40 mm | — | 58 | $356.25 | 82 | Amazon |
| 4 | Automatic (Sistem51) | — | 30 m | 42 mm | — | 41 | $275.00 | 78 | Amazon | |
| 5 | Automatic (Miyota 821A) | Mineral | 100 m | 45 mm | — | 58 | $440.00 | 74 | Amazon | |
| 6 |  | Automatic (Powermatic 80) | Sapphire | 100 m | 35 × 39.5 mm | ≥ 14.2 cm (5.6″) | 76 | $795.00 | 63 | Amazon |
| 7 |  | Automatic (Powermatic 80) | Sapphire | 100 m | 40 × 44.5 mm | ≥ 16 cm (6.3″) | 76 | $850.00 | 61 | Amazon |
Amazon.com prices as of November 3, 2026, 18:15 UTC — details. third-party = sold by a marketplace seller, not Amazon (warranty may differ); ships later = not in stock today, never crowned best value.