Noni offers custom penta prisms according to your specific requirement. A pentagonal (penta)  prism is an optical element characterized by two internal reflections of light rays incident on the first face of a pentagonal prism, with the outgoing rays being turned at a certain angle. These prisms are commonly used in optical devices such as camera viewfinders, image viewing systems, and measuring instruments. A pentagonal prism has an angle of 90 degrees between the direction of the incident light and the direction of the outgoing light. Regardless of the angle of incidence on the first side, the outgoing light turns the incident light to a certain angle. In addition, the image made by the pentagonal prism is neither rotated nor specularly reflected. Uses for this type of prism also include use in optical measuring devices such as rangefinders, telescopes, and holographic cameras.