Sellita SW400-1 caliber: dimensions and drop-in group

Used in: a large-diameter Sellita automatic, for oversized three-hand watches.

A large 14 ligne automatic with date at 31.00 mm x 4.67 mm, a scaled-up SW200-1 for big cases. Its 31.00 mm diameter is its own footprint and does not fit a 25.60 mm case.

Drop-in group: 13 1/4 ligne large automatic date (31.00 mm x 4.60 mm). Matching diameter and height is necessary but not sufficient. A donor is only a true drop-in when the dial-foot positions, hand-hole sizes, stem length and calendar layout also match. Two movements can share a case and still need a new dial, re-broached hands or a cut-to-length stem.