Barska 4x20 Electro Sight Carry Handle Scope
"The 4x20 Electro Sight M16 Carry Handle Riflescope is constructed specifically to fit the carry handle of an M16 or AR-15 rifle. The Electro Sight's base easily mounts to the inside track of these rifles carry handle. A small see-through hole has been provided at the bottom of the sight's base so that the rifle's iron sight is still visible and fully functional with the Electro Sight mounted. The scope offers a 20mm tube with a Mil-Dot reticle and multicoated optics. It is endowed with 1/2"" MOA adjustments of the windage and elevation turrets. Protected by a Limited Lifetime Warranty."