ETA 901.001 caliber: dimensions and drop-in group

Used in: a small Swiss three-hand quartz caliber, in compact and ladies quartz watches.

A small three-hand quartz caliber at 17.20 mm x 3.20 mm for compact cases. Its small footprint has nothing in common with the 11 1/2 ligne core, so it pairs only with same-size small quartz calibers.

Drop-in group: ETA small-form quartz (17.20 mm x 3.20 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.