The Trijicon TA31 ACOG 4x32 Scope w/ Red Dual Illumination Doughnut Reticle features Dual Illumination (Fiber Optic provides daylight illumination and tritium illuminates reticle at night). The reticle of the Trijicon TA31 ACOG 4x32 Tactical Scope ranges out to 800 Meters for 5.56(.223 cal) and hit fast in any light. Trijicon ACOG 4 x 32 Rifle Scopes are internally-adjustable, compact telescopic sights with tritium illuminated reticle patterns for use in low light or at night. The Bindon Aiming Concept (BAC) scope features bright daytime reticles using fiber optics which collect ambient light. Trijicon 4x32 ACOGs Fiber Optics & Tritium Illumination Scope combine traditional, precise distance marksmanship with close-in aiming speed. Although Trijicon ACOG 4 x 32 Scopes w/ Donut Reticle have many features which are very advantageous for military use, they were developed by Trijicon without government funding. Designed for use with the M16 family, every feature of its mechanical and optical design was chosen for a single purpose: to provide increased hit potential in all lighting conditions - without failure-prone batteries. Specifications for Trijicon ACOG 4x32 Scope w/Dual Illumination: Manufacturer: Trijicon Objective Lens Diameter: 32 mm Magnification: 4 x Exit Pupil: 8 mm Finish: Matte Field of View, Linear: 36.8 ft at 100 yds Field of View, Angle: 7 degrees Eye Relief: 1.5 in Color: Black Weight: 9.9 oz Length: 5.8 in Adjustment Type: MOA Illumination Type: Fiber Optics/Tritium Fabric/Material: Forged Aluminum Shockproof: Yes Fogproof: Yes Package Type: Polymer hard case Magnification Type: Fixed Attachment/Mount Type: TA51 Country of Origin: USA Features of Trijicon 4x32 ACOGs Fiber Optics & Tritium Illumination Scope: Military-Grade Aluminum Alloy Housing Forged 7075-T6 aircraft aluminum alloy housing provides for a nearly indestructible sighting system Binding Aiming Concept (BAC) Trijicon ACOG models equipped with BAC allow use of the both-eyes-open aiming method along with scope magnification sighting for rapid target acquisition - in any light Longer Eye-Relief Maximum eye-relief for larger caliber rifles and large exit pupil for faster target acquisition Internally Adjustable Since only the prism housing moves, the ACOG is much more rugged than the conventional designs Trijicon Fiber Optics Automatically adjusts the brightest level and contrast of the reticle to available light conditions Trijicon Tritium Phosphor Lamp Aiming reticle glows in low-light conditions for quick target acquisition. Lamp is guaranteed to illuminate up to 15 years. Totally Battery-Free ACOG delivers increased hit potential in all lighting conditions - without the use of failure-prone batteries Broad Band Anti-Reflective Coated Lenses Multi-coated lenses provide superior clarity and light gathering capabilities with zero distortion Lifetime Warranty Package Contents: Trijicon ACOG 4x32 Scope w/Dual Illumination TA31 1 4x32 Scopecoat (TA64) 1 LENSPEN (TA56) 1 Lanyard Assembly for Adjuster Caps (TA71E) 1 Trijicon Logo Sticker (PR15) 1 ACOG BAC Manual 1 Warranty Card