Maxell Watch Battery SR521SW is a silver oxide low drain battery 1.55 V. Watch Battery SR521SW measures 5.8X2.1mm. It is mercury free and has a capacity of 16 mAh.
Interchange: Energizer 379, Renata 379, Varta V379, Rayovac 379, Duracell D379, Timex JA Citizen 280-59, Seiko SB-AC/DC, I.E.C SR521 (SR63)