Surefire 123A Lithium BatteriesThe best 123A lithium batteries available, bar none 123As outperform alkaline batteries 10 year shelf life * they're ready when you need them Optimized for use in SureFire flashlights, SureFire high performance lithium batteries pack a lot of power into a very small package. And unlike alkaline batteries, SureFire provide a 10 year shelf life, which means they will be ready when you need them, every time. Trust in the power and durability of SureFire