Watch Battery 399 - Renata is a silver oxide high drain battery 1.55 V.
It measures 9.5 X 2.7mm. Renata 399 is mercury free and has a capacity of 55 mAh.
Renata Switzerland is a leading manufacturer of premium button cells for watches and many electronic products.
Interchange: Energizer 399, Maxell SR727W, Varta V399, Rayovac 399, Duracell D395/399, Timex W, Citizen 280-44, Seiko SB-BP, I.E.C SR927 (SR57).