This 399 Silver Oxide Button Cell Battery is 1.55 V and has a capacity of 60 mAh.
This battery is a replacement for Eveready 399; Vinnic: S926; Renata 35; Duracell D399; Varta V399; RayoVac 399; Maxell/Toshiba SR927W; IEC SR57; Other # SG7,GP95
These are replacement watch batteries and replacement small electronics batteries.