The Glock Modular Optic System, available on Gen 4 34, Gen 4 35, and Gen 4 41
Glock engineers developed the modular optic system to simplify mounting of
popular optic sights without costly custom machining of the pistol's slide. Comes
with a cover plate for sightless shooting and four additional plates designed to work
with EOTech, Doctor, Insight, Meopta, Trijicon, C-More, and Leupold DeltaPoint.
Check out some cool interactive demonstrations on Glock's website here!