Leupold VX-3i 4.5-14x40mm CDS Duplex Reticle Matte Riflescope DIAMONDCOAT 2: exterior lens surfaces are treated with DiamondCoat 2, an ion-assist lens coating, for higher light transmission and the greatest level of abrasion resistance we've ever offered ARGON/KRYPTON BLEND, which nearly eliminates the effects of thermal shock, and reduces the diffusion of gases sealed inside your scope even more than our proven nitrogen technology already does TWIN BIAS SPRING ERECTOR SYSTEM: the twin bias spring exerts up to 30 percent more holding force on the erector, virtually eliminating erector system backlash and stress on the vital internal workings of the scope, for longer life 3:1 ZOOM RATIO: a versatile 3:1 zoom ratio erector system that is ideal for virtually any situation ONE INCH MAINTUBE: durable and compact, the one-inch maintube is lightweight and fits more legacy rings