GlobalPioneer Cal .338 Lapua Laser Bore Sighter Boresight / 338 Lapua Catridge Laser Bore Sight with Batteries Quality grade Aluminum 6061 T6 Casing Class IIIa 635nM Less Than 5mW, Avoid Direct Eye Exposure to Beam. Precision Laser Optics Sits perfectly in the chamber Quick and easy sighting and zero, No more wasting ammo Come with batteries