RAYOVAC 379 ( SR521sw )

Recognised as one of the largest and most trusted of battery manufacturers,

Rayovac watch batteries are chosen by watch professionals the world over

This battery is a direct replacement for the following battery numbers....
Citizen 44, SR57, SR927, SR927W, AG7(alkaline cell)

The physical dimensions of this battery are
Diameter 5.8 mm x Thickness 2.1 mm