ALEXANDRIA, Va., March 31 -- United States Patent no. 12,590,663, issued on March 31.
"Clean out plug" was invented by Thomas Mark Lobbezoo (Caledonia, Mich.).
According to the abstract* released by the U.S. Patent & Trademark Office: "A clean out plug for removably plugging a clean out opening in a fluid line has an externally threaded body with an upper surface having an opening into a cavity in the body which houses a reversable key which is removeable from said body, and which has a smooth surface on one side and a tool engaging projection on the reverse side. In a first position in the cavity, the key presents a smooth flush surface with said plug body, with said projection projecting down into said cavity. In its reverse second posi...