The HB-N104 Black Lens Hood from Nikon is a bayonet-type lens hood compatible with the 1 Nikkor 18.5mm f/1.8 Lens for Nikon 1 CX Format Mirrorless Cameras. Lens hoods are designed to block unwanted light from entering the lens and causing flares and ghosting on the image. The size of this lens hood is designed with the focal length of the 18.5mm lens in mind: long enough to deflect light but not so long as to be seen in the wide angle of view. Lens hoods also offer a degree of protection for the lens from accidental bumps. This lens has a 40.5mm filter thread to screw onto the lens.