Two small clips on the back secures the eyepiece onto your camera. - Replaces Nikon Eyecup DK-21. - 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 for Nikon DK-21 22mm to prevent light entry due to bulb shutter long exposure. A great accessory for all photographers. Compatible with Nikon DK21 D7000 D600 D80 D90 /D40 D50 D70S D90 D200 D300. Provides protection for the camera eyepiece and keep the camera viewfinder away from dust. Plastic body cushioned with soft rubber for comfort and protect your eyes. Brand Nikon SKU NI736EL0FEMTKNAFAMZ-112199 Model 35001053