Trijicon ACOG (Model TA31RCO-M4). It is on a LaRue Tactical RCO QD Mount that is ideal for AR15/M16 use with the relieved rear portion for charging handle clearance. Comes with the Trijicon Lens Pen, Scopecoat neoprene cover, and USGI KillFlash filter. No box or manual. Optic and mount are in excellent condition.