The Bushnell Professional Boresighter is for quickly adjusting scope or iron sights to align with the rifle or handgun barrel. The boresighter will put sighting-in test shots on the paper, requiring only minor expenditure of time and ammunition by test firing to achieve pin-point zero at a given distance. Because of the many variables involved in both ammunition and the firearm itself, final sighting in must be done by actual live firing. Includes: Boresighter; .17" arbor; .22-.27" arbor; 7mm-.35" arbor; .35-.45" arbor; carry case and paper instructions.