Remove the original rear sight. Glock provides a tool for this purpose, and any qualified gunsmith can easily perform this function.
Slightly loosen T.A.S. sight’s mounting screws.
Insert the T.A.S. sight dovetail into the original mating groove on the pistol and slide the sight to a central position.
Align the fully illuminated T.A.S. sight (i.e., you should not see any dark areas on the edges of the dot) with the center of the front sight blade.
Gradually tighten the T.A.S. sight mounting screws while checking that the front and rear sight are still aligned. Note! Check that the T.A.S. sight mounting screws remain tightened after intensive shooting.