Viewfinder Eyepiece Square type. Compatible with square viewfinder models of Nikon EM, EG, F-301, F-401, F-501, F-601, etc., for entry-level to mid-range cameras. There is no model number, and it was sold as a "viewfinder eyepiece." The bag is tattered and was found opened, but it is an unused item. See photo 3. It will be wrapped in a different plastic bag, and the tattered bag will be included. I think this item is now difficult to obtain.