Fotodiox Dedicated Bayonet Lens Hood, for Canon EOS EF 17-85mm f/4-5.6 IS EF-S USM Lens and EF-S 18-135mm IS f/3.5-5.6 Lens (Replaces Canon EW-73B)

Lens hoods extend and shade the end of lens preventing unwanted light straying into the lens. Since the end of the lens is extended, you get the benefit of some extra protection from accidental impact. Each dedicated lens hood was specifically created to match the specific focal length of the lens it was designed for. Photographers can easily attach the lens hood on the dedicated bayonet mount, and after usage mount the lens hood on the lens in reverse for a compact storage solution.