Spectrum Brands, Inc R9VL1 R9VL-1 Lithium Battery (9 Volt) by Rayovac

This lithium battery lasts longer than ordinary alkaline batteries with higher energy density, wider operating temperature range and lighter weight. Consumer-replaceable battery lasts on average two times longer than ordinary alkaline 9-volt batteries. Using the 10-year smoke alarm battery in your ionization smoke detector will give you a working smoke alarm for years.