Rubber expansion plugs with a nylon wing nut plug allow you to quickly allow your plumbing lines to keep water out during the winter. Known as expansion bolts, freeze plugs, rubber plugs, hole plugs, pipe or just pool plugs, you can use these expandable rubber plugs for pool returns, line cleaners and skimmers to prevent pipes from filling with water and freezing in the winter. This plug is designed for 2 inch pipe.