A lens hood is an essential part of your Nikon system. When the rays from a strong light source, such as the sun, strike the front surface of your lens at a shallow angle, they cause flare which can rob your photos of contrast and color saturation.
Lens hoods act to reduce stray light and minimize flare by casting a shadow across the front of the lens thereby restoring the lost color and contrast. Hoods also provide important shock protection should your lens be dropped or bumped.
Finally, genuine Nikon hoods are made of materials that prevent permanent bonding to the lens. Metal type hood for extra strength, screws into the front of the lens or filter.