The Wheeler EngineeringA(R) Professional Laser Bore Sighter uses a high power red laser and a high-strength magnetic connection to the barrel to deliver fast accurate bore sighting. This system works with virtually all firearms; rifles, shotguns, handguns. The magnetic connection to the end of the muzzle provides more precise alignment with the bore without the risk of damaging the bore, compared to arbor style bore devices. A machined aluminum body with soft rubber over-molding houses the laser module. Each unit is hand tuned during the manufacturing process with an innovative calibration mechanism. This allows for maximum precision, thus ensuring the best bore/optic alignment possible. Once precision calibration is completed the laser module is permanently secured in place insuring reliable performance and durability. Molded plastic storage case included. Runs on a single Lithium 123A battery (included). Makes initial scope adjustment simple, fast and precise