Pixco HB-40 Bayonet Mount Lens Hood for Nikon AF-S NIKKOR 24-70mm f/2.8G ED Lens Hood type: HB-40 Hood material: Plastic Hood color: Black Nikon AF-S NIKKOR 24-70mm f/2.8G ED 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.