Chamber the Sightmark Laser Boresight in your 7mm, .338 or .264 rifle like a regular cartridge and a red laser dot shows exactly where you're aiming. Range for sighting is 15-100 yards, with an operating temperature at -10 to 50 F/C. Ideal for hunters, competitive shooters and law enforcement, this device significantly reduces wasted cartridges and shells. Includes a carrying case, three AG3 batteries and instructions.