We had a backed-up sewer pipe. Utility came out and cleared it with a tool that they used at the exterior vent. It is just a 4-inch disc on the end of a rod that you plunge up and down inside the vertical vent pipe to release the clog. I want to get (or make) one of these should it happen again, but cannot find it while searching with a variety of search terms. What is this tool called? Has anyone made one of these? Thanks in advance!