Sightmark Chamber Laser Boresighters - This easy boresighter is caliber specific. Simply chamber the boresight like a regular cartridge, and the laser will show right where the rifle aims. Look through your scope and adjust the crosshairs to the laser. It will reduce the amount of ammo and time by utilizing the actual line of fire to sight in the scope. Includes Batteries Carry caseCompact systemEasy to pack and travelReduces ammo useFastest sighting systemCaliber specific