With long eye relief, a fast-focus eyepiece, fully multi-coated lenses and resettable MOA turrets, there's no compromising on the Crossfire II. Clear, tough and bright, this riflescope hands other value-priced riflescopes their hat. The hard anodized single-piece aircraft-grade aluminum tube is nitrogen purged and o-ring sealed for waterproof/fogproof performance. With long eye relief, a fast-focus eyepiece, fully multi-coated lenses and resettable MOA turrets, there's no compromising on the Crossfire II. Clear, tough and bright, this riflescope hands other value-priced riflescopes their hat. The hard anodized single-piece aircraft-grade aluminum tube is nitrogen purged and o-ring sealed for waterproof/fogproof performance. 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 - 30mm 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 - Nitrogen 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. Capped Reset Turrets - Allow re-indexing of the turret to zero after sighting in the riflescope. Caps provide external protection for turret. Adjustable Objective - Adjustment for rifle scope's objective lens provides image focus and parallax removal. Fast Focus Eyepiece - Allows quick and easy reticle focusing.