100% brand new Description: Easy-to-use， self-contained boresighting system fits in the chamber of your rifle or pistol and projects a powerful red laser beam aligned with the bore axis for sighting to the point-of-aim without firing a shot. Works with scopes， holographic red dot sights， and variety sights. Durable， machined brass housing looks like a cartridge case but actually contains the entire laser system and batteries. Insert the batteries and screw the cap on the housing to turn on the laser; remove the batteries to turn off. Insert the entire assembly into the chamber， gently close the action， and aim at a target 20-30 yards away. Adjust windage and elevation of the scope or sights so point-of-aim is zeroed on. Product Details： New Cartridge Laser Boresighter is designed for 12 Gauge shotgun chambers Chamber-Mounted Laser Helps You Sight In Rifle Or Pistol Without Firing A Shot Features: Material: Copper Laser wavelength， 632-650 nm. ＜5mw Sighting range， 10-75yards. Dot Size: 1.5" @ 100 yds Package included:Battery: 3x AG5 (included)