Caliber reference
Ronda 515 caliber: dimensions and drop-in group
The published footprint of the Ronda 515 and which movements share it.
Used in: a common Swiss three-hand quartz movement in mid-range quartz watches.
A quartz caliber that shares the 25.60 mm 11 1/2 ligne diameter. It is not a mechanical donor: swapping a quartz Ronda for an automatic ETA changes power source, height and hand heights entirely. It swaps with the same-size Ronda 513S and 6203.B quartz calibers.
Drop-in group: Ronda 11 1/2 quartz three-hand (25.60 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.