The Sightmark Universal Red Laser Boresight provides the most convenient and accurate method for sighting in rifles and pistols of all types. Simply place the base of the boresight onto the end of the barrel of your weapon and it will attach magnetically. A laser dot will show exactly where your gun is aiming; it's easy to sight in any scope without firing a single shot. Includes a carrying case, three (3) AG3 batteries, and instructions. Range for Sighting 15-100 Yards.