Professional Laser Bore Sighter uses a high power daylight visible green laser and a high-strength magnetic connection to the barrel to deliver fast accurate bore sighting. This system works with virtually all rifles, shotguns, and 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 great 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 is included. Sighter runs on a single 123A battery(included).