Silver oxide is a popular type of battery because of its greater durability, high energy-to-weight ratio and tolerance of high current loads. Zinc and silver oxide are used to make the negative and positive electrodes in a potassium hydroxide or sodium hydroxide electrolyte. Its only major disadvantage is in the comparative higher cost of the silver. It is very efficient at small sizes like button batteries. As the cells also contain mercury care must be taken when recycling. SR927W Silver Oxide Watch Battery 1.55v