Wide Zoom Lens - LS2ST1 "To support optimal projector installation and performance in a wide range of environments, seven types of optical lens ranging from short-throw to long-throw lens are available with glass materials for better focus and large apertures for a brighter image. The lenses are made in Japan to ensure the highest quality. Zoom Ratio: 1.18:1 Throw Ratio: 1.14-1.34 (PX9210) Throw Ratio: 1.1-1.3 (PU9220) Click here to understand more about Professional High Brightness Installation Projectors"