Two small clips on the back secures the eyepiece onto your camera. Replaces Canon Eyecup EG. Custom designed soft-touch eyecup to provide cushioning around the camera's eyepiece. Block out unwanted light from your viewfinder. Useful for eyeglass wearers and others to keep the tip of the nose from touching the camera body. Replacement Eyecup compatible with : Canon EOS 5D Mark III 5D3, 5D Mark IV 5D4, 5DSR, 5DS, 7D, 7D Mark 2, 1D X, 1Ds Mark III , 1D Mark IV, 1D Mark III Camera Provides protection for the camera eyepiece and keep the camera viewfinder away from dust.