H-K9L glass Roof Prism for compact binoculars

The Roof prism can rotate and reverse the image and deflect light with a 90 degree; Besides, it is suitable for telescopes and any optical instrument that needs to flip the image from the objective lens, open the right side and bend at 90 degree; to maintain the correct visual direction.  Roof prisms have a small volume and can align the objective and eyepiece in a straight line, making them commonly used in extremely compact binoculars.