Energizer 635236 Ultimate Lithium 9V Battery Energizer Lithium 9v Pack of 1 Introducing Energizer Ultimate Lithium, the most technologically advanced battery, for consumers who want a battery that offers the best performance. Energizer Ultimate Lithium is ideal for smoke alarms, lasting 65% longer than alkaline 9v, also with a 10 year shelf life Energizer Ultimate Lithium can help your device work for longer, operate and perform better and keep running even in cold temperatures. It is also 1/3 lighter than an alkaline battery great for when you are using portable devices. Replacement for: 1604AU, 6LR61, X22, PP3, 9v