1. Made of hollow rubber, it provides a soft touch, even when wearing glasses. 2. Offers a cushioning effect around the viewfinder, especially suitable for eyeglass wearers. 3. The eyecup primarily prevents light from entering the viewfinder during long B-bulb exposures. An essential small part for taking pictures. 4. Prevents the eyecup from being scratched when the camera is not in use; prevents debris from entering the viewfinder when the camera is stored. 5. How to use: Install it on the outside of the eyepiece to prevent stray light from entering and facilitate clear framing. When using, first remove the rubber eyecup and then insert the eyecup into the viewfinder's external slot. Function: Protects eyes and viewfinder, making the SLR world clearer Applicable models: for cameras with 18MM aperture 5D 20D 30D 10D D60 66, 300, D30, 10, 300V, 88, 100, EOS500, EOS500N, 700, 750, 850, 1000N, 1000FN Color: Black Material: Rubber Package contents: 1 * Camera viewfinder eye mask