Chamber the Sightmark Laser Boresight in your .243, .308 or 7.62x51 rifle like a regular cartridge, and a red laser dot shows exactly where you're aiming. Ideal for hunters, competitive shooters and law enforcement, this device significantly reduces wasted cartridges and shells. Simply adjust your sights or scope, and save your extra ammo for the hunt. This device is tested and recommended by the National Tactical officers Association. Includes a carrying case, three AG3 batteries, and instructions.