A13 measures 7.9 mm in diameter and 5.4 mm in height (max dimension per IEC) — verify against your battery holder.
Measure with a caliper on the old cell: a 0.5 mm difference can mean a different reference (e.g., the CR family: 1.6/2.5/3.2 mm).
All A13 prints are controlled to the size standard with 0.02 mm caliper checks in our final inspection.
