Optimize the performance of your LaserMax Guide Rod Laser sight by installing a fresh set of batteries at least once a year. Reliable, lightweight and powerful, LMS-319 Silver Oxide batteries operate flawlessly across a wide range of temperatures, feature a 5-year shelf-life and are sleeved to ensure quick and trouble-free installation. Please refer to the LaserMax Operator's Manual or Battery Compatibility Chart to confirm correct part selection.