The addition of a lens hood can help prevent flares--those circles of light that can accompany images where a strong light source is just outside the fame. These types of lens flares occur when indirect light rays pass through the front lens elements but don't make it all the way through to the image sensor.

EW-73II Lens Hood is designed for the Canon EF 24-85mm f/3.5-4.5 Lens. 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. This dedicated lens hood is designed to match the specific focal length of the lens it was designed for.

Replacement for Canon EW-73II Lens Hood
Compatible with Canon EF 24-85mm f/3.5-4.5 Lens
Prevent unwanted stray light from entering the lens
Extra protection from accidental impact
Designed to match the specific focal length of the lens