This rail end cap, or dishrack stop clip, is a genuine OEM Frigidaire/Electrolux replacement part for your dishwasher. This part keeps the rack in your dishwasher from sliding out by blocking the dishrack roller wheels from exiting the track.  Over time, wear and tear can reduce the friction holding the caps in place and they may pop off, thereby allowing your dishrack to exit the tracks.  Fortunately, this is a very easy repair, to complete it you only need a flat blade screwdriver. Use the screwdriver to pry the locking tab open on the cap, located at the front of your upper dishrack. Pull off the end cap and lock the new one into place.