The Trijicon ACOG (Advanced Combat Optical Gunsight) is a fixed power, compact riflescope with an illuminated reticle pattern for use in bright to low/no light. The ACOG is designed to be extremely durable and reliable. Combining traditional, precise distance marksmanship with CQB speed, many variants include a bullet drop compensated (BDC) reticle. Every feature of its design was chosen for a single purpose: to provide increased hit potential in all lighting conditions. The ACOG 3.5x35mm riflescope has remained a favorite among competitive shooters, law enforcement and freedom-loving civilians everywhere. The TA11MGO-M249 3.5x35 ACOG is a Machine Gun Optic (MGO) designed specifically for the M249 weapon system. The MGO provides the shooter enhanced target identification and increased hit probability out to 1000 meters utilizing the Bullet Drop Compensator. With threaded bosses on the eyepiece housing, the TA11MGO-M249 allows the end user to incorporate the Trijicon RMR sight for close combat situations or any other target designators. The TA11MGO-M249 incorporates dual-illumination technology using a combination of fiber optics and self-luminous tritium. This allows the aiming point to be illuminated without the use of batteries. The tritium illuminates the aiming point in total darkness, and the fiber-optic self-adjusts reticle brightness during daylight according to ambient light conditions. This allows the operator to keep both eyes open while engaging targets and maintaining maximum situational awareness. Comes with TA51 Flat Top mount and ARD objective lens insert.