Energizer SR63 Button Battery, 1.55V, 5.8mm Diameter

The Energizer Low drain watch battery uses a zinc/monovalent silver oxide chemical system and delivers a nominal voltage of 1.55 volts with a capacity of 16 mAh, tested under a 47 kΩ discharge at 20°C down to 1.2 volts. It operates effectively within a temperature range of -10°C to 60°C and features a low self-discharge rate of less than 5% per year at 20°C. Weighing approximately 0.23 grams, this battery provides reliable, long-lasting power for small precision timepieces.

Equivalent mercury containing battery range
Long shelf life so they are always ready when you need them
They have been extensively tested so you will never be disappointed