Take the guesswork out of zeroing in with the Aim Sports Brass Cartridge Laser Boresighter precision-engineered for .243 Winchester .308 Winchester and 7mm-08 Remington calibers.Designed for simplicity speed and accuracy this cartridge-style boresighter offers a hassle-free way to align your sights or optics without firing a single round.Crafted from high-quality brass the boresighter mimics the exact dimensions of your ammunition for a snug chamber fit ensuring true-to-bore laser alignment.Unlike traditional muzzle-mounted systems this chamber-mounted design allows for quick and reliable setup - simply insert the boresighter into your rifle like a live round and start dialing in your optic.Featuring a powerful 5mW red laser it provides a clear point-of-aim for precise sight adjustments helping you save time conserve ammunition and improve your shooting confidence.Compact and lightweight the unit is powered by an LR41 battery (included) making it perfect for your range bag or field kit.Features / SpecsAim Sports Inc.PJBS308Red Laser Bore Sight Tool 5mW Red Laser435/355NM WavelengthLR41 Battery TypeSits inside chamberAllows you to adjust Iron Sights/ScopesPerfect for Sighting InBrass CasedNatural FinishFits Firearms Chambered in:.243 Winchester.308 Winchester7mm-08 Remington