Swatch Sistem Solaire YIS414

Irony is Swatch's name for its steel-cased watches, and the Sistem51 Irony keeps the 42 mm size and 13.8 mm thickness of the plastic models. The automatic movement has 51 parts anchored to a single central screw and a 90-hour power reserve, and it is sealed into the case with structural adhesive, so it cannot be serviced.

Among the steel models, the Sistem Navy (YIS409) also has a grey dial, while the Sistem Earth (YIS400) and Sistem Soul (YIS402) are blue and the Sistem Arrow (YIS403) black. The plastic Sistem51 models, such as the silver-dial Sistem Arlequin (SUTW402), share the movement and case size but not the steel.