Corner cube retroreflectors are designed to reflect any ray or beam entering the prism face, regardless of the orientation of the prism, back onto itself. A mirror will only do that at the normal angle of incidence. As a result, corner cube retroreflectors are ideal where precision alignment is difficult or time-consuming. They feature three total internal reflections and will function even at very large angles of incidence. TECHSPEC® N-BK7 Corner Cube Retroreflectors are made from precision N-BK7 for use in a variety of visible light applications.