This is one of the simplest bore sighters you will ever use. Simply chamber the bore sight like a normal cartridge and a laser will shoot out of the barrel showing exactly where your rifle or shotgun is aiming. This will save time and ammunition as only a few shots will have to be fired for fine tuning. Notes:Caliber or gauge specific bore sightRed laser has a wavelength of 632 to 650, uses less than 5 milliwatts approximately 1 hour of battery lifeSighting range 15 to 100 yardsWill display a 2" dot at 100 yardsBrass outer caseOperating temperature 14 degrees F to 122 degrees FIncludes a carrying pouch