Reduce wasted ammo and keep precision accuracy at your fingertips with the Firefield Universal Red Laser Brass Boresight. The fastest gun zeroing and sighting system there is, the laser bore sight attaches easily to any rifle to begin shooting in minutes. Strong magnet holds the boresighter to the barrel muzzle, allowing the sighter to work with any caliber firearm. Once placed on the end barrel of the Firearm, the red laser dot appears exactly where the barrel is pointed, allowing the weapon sights to be adjusted to the theoretical impact point. Live fire is only needed to fine tune for bullet drop and windage compensation. Whether used for hunting or target shooting, Firefield bore sights enhance every adrenaline-filled moment. IncludedBatteriesType: AG13Quantity: 3 FeaturesFits Barrel Sizes .17 HMR - .50 CalPrecision AccuracyReliable and DurableAluminum ConstructionCompact and LightweightFastest gun zeroing & sighting system