Sellita SW300-1

Introduced around 2011, the SW300-1 is the second generation of Sellita's SW300 caliber family, engineered as a direct drop-in alternative to the ETA 2892-A2—a movement ETA introduced in the mid-1990s that became the standard for higher-end Swiss automatic watches. The SW300-1 improves on that architecture in one notable respect: it uses 25 jewels instead of the 2892-A2's 21, with the extra jewels added at the barrel arbour to reduce friction.

Sellita has been supplying the independent watchmaking trade since around 2008, and the SW300-1 grew in prominence as ETA progressively restricted outside sales of the 2892-A2. It ships in two primary sub-variants: SW300-1 a, which includes a quickset date at 3 o'clock, and SW300-1 b, a cleaner no-date version. A sister caliber, the SW330-1, extends the family to include a central GMT hand.

In 2021, Sellita retrofitted the entire SW300 family with a new barrel and mainspring assembly, extending power reserve from 42 to 56 hours—eclipsing the ETA 2892-A2 on that specification. Four named accuracy grades are available: Standard (±30 s/day), Special/Elaboré (±20 s/day), Premium/Top (±15 s/day), and Chronometer (−4/+6 s/day, meeting COSC criteria). Anti-shock protection is Novodiac on Standard and Special grades and Incabloc on Premium and Chronometer grades.