Porro is a type of optical prism used in binoculars and telescopes to invert and revert images. It consists of two prisms arranged in a specific way, allowing for a more compact design while maintaining a correct orientation of the viewed image. This design is commonly found in Porro prism binoculars, which are popular for outdoor activities like birdwatching and hiking. The Porro prism was named after the Italian optician Ignazio Porro, who developed this optical system in the 19th century. Its unique structure provides a wider field of view compared to other prism types, making it a favored choice for many users seeking quality optics.