Trijicon's ACOG (Advanced Combat Optical Gunsight) is a fixed power, compact riflescope with an illuminated reticle pattern for use in bright to low/no light with legendary durability and reliability. Every feature of its design was chosen for a single purpose, to provide increased hit potential in all lighting conditions. Fewer moving parts than a variable optic equals more durability, and the forged 7075-T6 aircraft-aluminum-alloy housing provides for a nearly indestructible sighting system. Multi-coated lenses provide superior clarity and light-gathering capabilities with zero distortion. The ACOG is dry-nitrogen-filled to eliminate fogging and waterproof to 100 meters. It is shock-resistant, proven to withstand recoil from 22LR up to 50 BMG, and easily passes U.S. military drop test requirements. This ACOG features a dual illuminated red chevron 223 ballistic reticle calibrated to 800 meters. It includes a TA51 flattop adapter mount and has a black finish. This model includes Trijicon's 3.25 MOA RMR type two LED red dot and has a Tritium dual illuminated red crosshair reticle.Adapted from the battlefields, US forces have begun improving this proven Trijicon ACOG scope by adding a small red dot sight on top for close encounter missions. Trijicon has now created a similar model for the public, the TA31-D-100549. The main Trijicon scope provides a dual-illuminated reticle using fiber optics and tritium for bright aiming point in any light condition. The ranging reticle allows for bullet drop compensation out to 800 m without any manual adjustments. A Trijicon RMR Type 2 sits on top with a 3.25 MOA aiming dot. Features: Always on, always ready - most ACOG models are battery free, featuring a tritium/fiber optic illuminated reticle that automatically adjusts the brightness based on available light "Both eyes open" design - shooting using the Bindon Aiming Concept (BAC) allows for improved situational awareness Combat proven - no other magnified optic has been used more in combat than the ACOG Take control - several ACOG models are designed with a user adjustable brightness setting powered by a single AA battery, the 3.5x35 LED and 4x32 LED models both offer six adjustable brightness settings Outstanding clarity - the quality of the glass and multi-coated lenses maximize light-gathering capabilities and clear field of view with zero distortion Shock-resistant - proven to withstand recoil from a .22 LR to a .50 BMG and everything in between, easily passes US Military drop test requirements Rugged, reliable housing design - fixed-power design allows for minimal moving parts to create a nearly indestructible sighting system Exact target distances and holds - most ACOG models feature a bullet drop compensating and target-ranging reticle for decisive aiming Waterproof - exceptional waterproof performance that exceeds military standards, dry nitrogen-filled to eliminate fogging Fiber optics and tritium power and illumination source