Retro-reflecting cubes
Corner Cube Prisms reflect any ray or beam entering the prism face back onto itself. The reflectors are designed for applications where precise alignment is difficult or time-consuming. Mounted in an aluminum body and secured with RTV potting cement, the cubes are easily adapted to various mounting arrangements via two 1/4-20 tapped holes. The prisms are silvered to decrease polarization effects and increase field of view.
Edmund Scientific, Barrington, NJ