A pipe plug is a device used to block off a pipe temporarily. It’s often used for testing or maintenance purposes, to isolate a section of pipe from the rest of the system. Pipe plugs come in various shapes and sizes, typically made of materials like rubber, plastic, or metal, depending on the specific application and the type of fluid or gas being transported through the pipe. They can be inserted into the pipe and then expanded or tightened to create a seal, preventing the flow of substances through that section of the pipe.