Chamber the Sightmark .50 Cal Red Boresight in your .50 caliber rifle just like a regular cartridge and a red laser dot will show you exactly where you're aiming. Perfect for hunters, competitive shooters and law enforcement, this Boresight helps minimize wasted ammunition by allowing fast and precise adjustments to your sights or scope. Save your extra ammo for the real action by fine-tuning your accuracy with this efficient tool. The package comes with a carrying case, one CR2 battery and easy-to-follow instructions, making it a convenient and reliable choice for zeroing your rifle.