For unknown reasons, all sockets outside my home were installed in round (lighting) junction boxes, so the sockets could not cover them properly. These overlays made it possible (finally) to seal the boxes against water and insects, as well as to fit proper waterproof covers for the outside sockets. The price is really unfortunate for what they are (I was tempted to buy a 3D printer and make them myself) but if they are what you need they will do the trick.