This HC-N101 Front Lens Hood Cap for 1 Nikkor 10mm f/2.8 Lens from Nikon is a front cap for the HN-N101 lens hood for the 1 Nikkor 10mm f/2.8 lens. It mounts on the lens hood to protect the front lens element when the lens isn't being used.
For 1 Nikkor 10mm f/2.8 lens hood HN-N101