Vortex Viper HS riflescopes offer hunters and shooters an array of features sure to be well received. Built from a single piece of aircraft grade aluminum, creating a tough foundation for this optic, it is O-ring sealed and argon gas purged for waterproof, fogproof reliability. Vortex's XR fully multi-coated lenses crafted from XD low dispersion glass ensure maximum light transmission with unparalleled resolution and color fidelity. This second focal plane scope features the Dead-Hold BDC reticle. The Dead-Hold BDC utilizes a hash marked design that helps eliminate guesswork on holdover and windage corrections. Great for shooting at varying ranges where estimating holdover is of concern.