Sightmark Sm39019 Boresight Laser 44 Mag Brass Useful For Initial Sighting Your Pistol, Or as a Training Aid For "Quick Draw" drills, The Sightmark .44 Magnum Boresight offers a Quick And Easy Way To Sight In Your .44 Magnum Pistol. Range For Sighting Is 15-100 yards, With An operating Temperature at -10 To 50 F/C. Includes a carrying Case And Three (3) Ag3 Batteries. Caliber: 44 Mag Style: Laser Material: Brass Battery: 3 Ag3