Porro prisms are optical devices used in binoculars and other optical instruments to invert and revert images. They consist of two prisms arranged in a specific way, allowing light to enter from one side and exit from the other while maintaining a compact design. This configuration provides a wider field of view and enhances depth perception. The unique design of Porro prisms results in a longer optical path, which helps to improve image quality. They are commonly found in binoculars due to their ability to produce bright and clear images, making them popular for outdoor activities like birdwatching and hiking.