The AG2 or LR59 is the alkaline designated name for this battery. The silver oxide version is called SR726SW, SR726, SR726W, SR59 and a few other labels. Zinc air 196, 396, 397 hearing aid batteries have the same physical dimensions. With a Diameter of 7.9mm and Height of 2.6mm. The average capacity for alkaline AG2/LR59 is 26mAh. Capacity for silver oxide SR726SW is 33mAh. Hearing aid batteries of this size have an average capacity of 32mAh.
The silver oxide, alkaline and hearing aid batteries all have the exact same height and diameter. Silver oxide batteries are used for more sensitive electronics like watches. Alkaline AG2 batteries are used in small toys and lights and other electronics which don’t require a reliable voltage.
AG2 Battery Equivalents and Cross Reference
SR726SW Battery Equivalents and Cross Reference
Alkaline AG2 nominal voltage is 1.5 volts but through use the voltage drops. Cut off voltage is 0.9 volts. Some devices have their own cut off voltage and could be 1 or 1.2V. With a average capacity of 26mAh these alkaline button batteries are mostly used for small electronics where constant voltage is not important. It is important to use silver oxide batteries where sensitive electronics are concerned. Silver oxide has a constant voltage over its lifetime whereas alkaline voltage declines with use.