The Red Laser Bore Sight Kit includes the .223 red laser modular bore sight (MBS223) that allows you to choose between two battery options: the original 3 LR41/AG3 batteries for a compact bore sight, or the new external battery pack with long running (20+ hours!) 2 AAA batteries. Both systems are included with this kit along with four top arbors: AR243, AR3006, AR264 and AR762 to allow you to bore sight most major calibers. The AR243 arbor is used to bore sight all 308 based calibers- 243, 7mm-08, 260 Remington, 308/7.62x51, 338 Fed as well as 444 Marlin, 7mm STE, etc. The AR3006 arbor is used to bore sight 30-06, 25-06, 270, 280, 35 Whelen, 300 Savage, and some Mauser calibers. The AR264 arbor is used to bore sight many magnum calibers (7mm, 300 and 338 Win Mag, 240/300/340 Weatherby, etc). The AR762 arbor is used to bore sight 7.62x39, 220 Swift, 303 British, 35 Remington, and others. Quickly and easily adjust and dial in optics on your rifle Includes the Modular Bore Sight 223 Includes four arbors- AR243, AR3006, AR264, and AR762 Machined out of solid brass to avoid scratching the chamber and to maintain close tolerances Zippered pouch to store bore sight and arbors included Comes with two AAA Panasonic batteries