Dial in the firearm fast and easy with the Weaver Magnetic Boresighter. This handy tool makes quick work of scope sight-ins; saving time, money and the headache of wasting rounds while trying to zero ther firearm. The unit magnetically attaches to most firearms and features an internal target for rapid adjustments. Simply align the scope's reticle with the boresighter's specialized internal target for reliable preliminary sight-in. Lightweight and compact, the Weaver Magnetic Boresighter is a must-have for any shooter's range bag.