Professional Retical Leveling System: The Wheeler Professional Reticle Leveling System is a precision tool and technique designed to allow a scope to be perfectly leveled on any firearm with ease. CNC machining, factory adjusted calibration set screws, anodized aluminum construction and protective molded case put this instrument in a class of its own. The system is comprised of two machined aluminum level housings calibrated to their integrated levels. The Barrel Clamp Level is attached to the guns barrel while the smaller Reference Level is placed on scope base, bottom half of a ring or other flat surface perpendicular to the vertical axis of the gun. The gun is then rota Mfg: Wheeler Engineering