ACOG 3.5x35 scope with Red Horseshoe BAC Reticle and Target Reference System-the ranging reticle is calibrated for 5.56 (.223 cal) flat-top rifles to 1000 meters. Daytime illumination is provided by fiber optics and Tritium illuminates the scopes at night.Specifications and Features: Thumbscrew Flattop Adapter (TA51) Length x Width x Height: 8 in x 2.1 in x 2.9 in Weight: 17.6 oz. (498.95g) Magnification: 3.5x Objective Size: 35mm Reticle Pattern: Horseshoe Dot Day Reticle Color: Red Night Reticle Color: Red Bullet Drop Compensating (BDC): Yes Caliber: .223 / 5.56 Bindon Aiming Concept (BAC): Yes Illumination Source: Fiber Optics & Tritium Power Source: Fiber Optics & Tritium Adjustment: 1/2 MOA per click Eye Relief: 2.4 in. (60.96mm) Exit Pupil: 0.39 in. (9.91mm) Field of View (degrees): 5.5deg Field of View (feet): 28.9 ft. @ 100 yds. (9.63m @ 100m) Mount: Flattop Thumbscrew Mount (TA51) Housing Material: Forged Aluminum Finish: Matte Black