Ultralife introduced the world™s first long lasting Lithium 9-Volt over 20 years ago, with over 100 million sold. Our Lithium 9-volt battery is a consumer-replaceable battery that lasts up to 5 times longer than ordinary alkaline 9V batteries and 10 times longer than carbon-zinc batteries. It has the highest energy density, flattest discharge voltage curve, longest shelf life, widest operating temperature range, and lightest weight of any comparable 9-volt battery. A 10-year shelf-life makes its 9-volt battery the choice for major smoke alarm manufacturers for their premium lines of 10-year ionization-type smoke alarms. Since it is a consumer-replaceable battery, consumers can instantly upgrade any application requiring a 9-volt battery.