This 1/2 AA battery has a nominal voltage of 3.6V and a chemical makeup of Lithium Thionyl Chloride (LiSOCl2). Lithium Thionyl Chloride has the highest energy density of any practical Lithium battery chemistry, three times greater than Alkaline (Zinc Manganese Dioxide) batteries. It also has the widest operating temperature range of -55°C to + 85°C. Self discharge is at less than 1% per annum at 20°C, giving an effective shelf life of 10 years.