Ronda 4220.B caliber: dimensions and drop-in group

Used in: a Swiss three-hand quartz caliber at the 12 1/2 ligne size, in larger quartz watches.

A three-hand date quartz caliber at 28.00 mm x 4.40 mm, a size up from the 11 1/2 ligne 515. It matches the diameter of the 5030.D chronograph but has no chronograph train, so the two are not interchangeable.

Drop-in group: Ronda 12 1/2 quartz three-hand (28.00 mm x 4.40 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.