The solid one-piece aircraft-grade aluminum alloy construction makes the Diamondback riflescope virtually indestructible and highly resistant to magnum recoil. Argon purging puts waterproof and fogproof performance on the agenda, and advanced fully multi-coated optics raise an eyebrow when crystal clear, tack-sharp images appear in the crosshairs. 3.5-10x50mm riflescope is ideal for big game, predator/varmint, muzzleloader, slug shotgun, and long range applications. Dead-Hold BDC reticle has a customized design that helps eliminate guesswork on hold-over and windage corrections. Good for any hunting or shooting at varying ranges where estimating hold-over would be a concern. Fully Multi-Coated: Increases 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. Tube Size: 1-inch diameter. Single-Piece Tube: Maximizes alignment for improved accuracy and optimum visual performance, as well as ensures strength and waterproofness. 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 the riflescope 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 low-glare matte finish helps camouflage the shooter's position. Precision-Glide Erector System: Uses premium components in the zoom lens mechanism to ensure smooth magnification changes under the harshest conditions. Capped Reset Turrets: Allow re-indexing of the turret to zero after sighting in the riflescope. Caps provide external protection for turret. Fast Focus Eyepiece: Allows quick and easy reticle focusing.