Wheeler Pro Retical Leveling System - The Wheeler(R) 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. Precision tool for scope reticle alignmentFactory calibrated Reference LevelMaximize accuracy potentialTunable Barrel Clamp LevelCNC machined aluminum level housingsProtective storage case