This is an original rubber eyecup made in Japan for the Nikon Z9/Z8/Zf. Install this eyecup on your camera to prevent light from entering the viewfinder from the side when looking through the viewfinder with the naked eye, making it easier to see the viewfinder and providing support for photography. You can also bend the rubber part of the eyecup to use it as an eyepiece. The rubber part is made of highly durable silicone rubber.