A 1/2 AA 3.6V 1200 mAh Lithium Thionyl Chloride from Saft. This battery is a non-standard sizes battery designed for reliability in specialist applications such as measuring devices, alarms and safety equipment, emergency transmitters, backup systems or real-time clocks. With an operating range from -60°C to 85°, C and resistance to wet environments are suitable to be used indoor and outdoor. They provide the high-performance and longer lasting life.