Vortex Viper 6.5-20x 50mm Rifle Scope - Effortlessly shrugging off recoil, moisture and darkness, the Viper's status as a premium riflescope won't be as easy to shake. Discover a riflescope with incredible performance features like premium, fully multi-coated optics, heavy duty Precision Force spring systems and the glass smooth Precision Glide Erector System-delivering all this and more at a price that should have pulled a few more hundreds from your wallet than it did. Dead-Hold BDC (MOA) The customized design of this reticle helps eliminate guesswork on hold-over and windage corrections. Good for hunting and shooting at varying ranges where estimating hold-over is a concern. XD Lens Elements Extra-low dispersion (XD) glass increases resolution and color fidelity, resulting in crisp, sharp images. XR Fully Multi-Coated Proprietary coatings increase light transmission with multiple anti-reflective coatings on all air-to-glass surfaces. Second Focal Plane Reticle Scale of reticle maintains the same ideally-sized appearance. Listed reticle subtensions used for estimating range, holdover and wind drift correction are accurate at the highest magnification. Aircraft-Grade Aluminum Constructed from a solid block of aircraft-grade aluminum for strength and rigidity. Waterproof O-ring seals prevent moisture, dust and debris from penetrating for reliable performance in all environments. Fogproof Argon gas purging prevents internal fogging over a wide range of temperatures. Shockproof Rugged construction withstands recoil and impact. Hard Anodized Finish Highly durable hard-coat anodization provides a low-glare matte surface and helps camouflage the shooter's position. ArmorTek Ultra-hard, scratch-resistant coating protects exterior lenses from scratches, oil and dirt. Capped Reset Turrets Allow quick re-indexing of the turret (no tool needed) to zero after sighting in the riflescope. Caps provide external protection for turret. Side Focus Adjustment located on left side of turret housing is easily accessible from shooting position. Provides optimal image focus and parallax removal.