Caliber reference
Ronda 585 caliber: dimensions and drop-in group
The published footprint of the Ronda 585 and which movements share it.
Used in: a small-seconds Swiss quartz caliber, in dress quartz watches with a sub-seconds dial.
A 500-family quartz caliber at 25.60 mm x 3.60 mm with small seconds at 6, taller than the centre-seconds 515. Its sub-seconds layout means it needs a small-seconds dial and does not swap with a centre-seconds 515.
Drop-in group: Ronda 11 1/2 quartz small seconds (25.60 mm x 3.60 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.