Red Laser Bore Sight 12 Gauge Barrel Cartridge Boresighter for 12ga ShotgunsRed Laser Bore Sight 12 Gauge Barrel Cartridge Boresighter for 12ga Shotguns ITEM DESCRIPTION Laser Cartridge Boresighter for 12 Gauge Shotguns This boresighter is designed for sighting in your shotguns without firing a shot. Simply install the included batteries, place the entire assembly into the chamber, and gently close the action. The sight will emit a straight red laser beam, providing precise reference for zeroing in your sights or scopes.