Optical Material: BK7 optical glass
Multi-coated optics
60/40 scratch/dig quality
Surface Flatness: λ/2
The porro-abbe prism is used to bend an image 90 degrees and rotate a vertical image horizontally. Porro-abbe prisms are also called double right-angle prisms. Two of them can be used to make an erecting system that are used in many models of binoculars and some telescopes. 2-3 of these prisms make for a great addition to any optical hobbyist's collection and add many possibilities for experimentation.