Trijicon 4x32 ACOG Riflescope with TA51 Mount (Gre, Forged 7075-T6 aircraft aluminum alloy housing Carry Handle Compatible Designed for use with standard M16/AR15 firearms with carry handles Bindon Aiming Concept ensures a far superior sense of balance, and a wider field-of-view. Combining these benefits with a magnified Trijicon sight gives you a considerable advantage over your target. Self Illuminated Red Triangle Reticle Calibrated for 5.56x45 NATO This red triangle reticle features dual illumination from Trijicon's proprietary tritium/fiber-optic technology. During day or nighttime a brilliant red triangle floats over the top of a long narrow post. Hash-marks upon the post provide hold-over points for long-range (800 m) target acquisition.