Caliber reference
Ronda 6203.D caliber: dimensions and drop-in group
The published footprint of the Ronda 6203.D and which movements share it.
Used in: the long-battery-life dual-time Swiss quartz caliber, in GMT-style quartz watches.
A dual-time quartz caliber at 26.00 mm x 3.30 mm with a second time zone and a battery life up to ten years. It shares the 6203.B's footprint and dual-time layout, differing mainly in cell life, and needs a matching multi-hand dial.
Drop-in group: Ronda 11 1/2 quartz dual-time (26.00 mm x 3.30 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.