The phot r 405mm telephoto metal lens hood is specifically designed for telephoto lenses the telephoto circular shaped lens hood has a screw mount fits over any 405mm lens filter or barrel thread lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens in addition since the end of the lens is extended you also get the added benefit of some extra protection from accidental impact the phot r lens hood is made from