The dedicated Vello HN-CP17 Lens Hood (40.5mm Screw-On) is specifically designed for use with Nikon's COOLPIX P7700 Digital Camera.
Lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. A dedicated lens hood is designed to perfectly match the specific focal length of the lens it was designed for. Moreover, this hood features a non-glare matte finish on the interior surface to further prevent or limit lens flare. And since the end of the lens is extended, you also get the added benefit of some extra protection from accidental impact.
This is a metal hood with a black matte finish.