Vortex Optics Diamondback Second Focal Plane Riflescopes The Diamondback 4-12x40 riflescope is one of multiple configurations in the Diamondback lineup and is ideal for big game, predator/varmint, muzzleloader, slug shotgun, and long range applications. Dead-Hold BDC reticle is good for any hunting or shooting at varying ranges where estimating hold-over would be a concern. Lenses are fully multi-coated for crstyal clear, bright images from dawn til dusk. The fast focus eyepiece allows for quick and easy reticle focusing. Metal on metal precision turrets offer the ability to zero reset after sight-in. A precision glide erector system ensures accurate tracking and repeatability. A solid one-piece tube with a hard anodized finish creates a shockproof and durable scope while helping camouflage the shooter's position. Argon purged and o-ring sealed the scope will deliver a lifetime of fogproof and waterproof performance.