The most unique feature of the system is the ability to easily calibrate the unit, in the firearm your sighting, to remove all pointing errors! Utilizing a stainless steel arbor coupled with a precision brass tapered rotating bushing and Derlin caliber adapters with brass bushings, the entire laser head is designed to rotate and is fully adjustable. With the ability to calibrate the unit at any time there is no doubt where the barrel is pointing. These units are so accurate they can be used to check the regulation of double rifles. The Universal Laser Bore Tool works with any firearm from .22 to .50 caliber. Each system includes a plastic molded carrying case, Laser Bore Tool(s),12 - 20 guage shotgun adapter, laser scope leveler, 4 Delrin caliber adapters, daylight laser target and instructions. This system can be used to sight-in your firearm or check the sights (without firing) at any time or place, including your hunting camp!