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-393 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 Operators Manual or Battery Compatibility Chart to confirm correct part selection.Features :Battery for old style Glock/SIG guide rod laser