Sightmark .40 S&W Premium Laser BoresightTested and recommended by the National Tactical Officers Association, the Sightmark Boresight significantly reduces wasted cartridges and shells. Chamber the device like a regular cartridge, and a red laser dot shows exactly where you're aiming. Simply adjust your sights or scope, and save your extra ammo for the hunt. Includes a carrying case, three (3) AG3 batteries, and instructions.