Specially designed to temporarily seal and stop off pipe ends remotely during fitting renewal or service line maintenance. Reusable, rugged, and lightweight made from Nitrile rubber and plated steel available in a variety of sizes, ranging from 1/2" through 2” Also used as a tamper resistant night cap to prevent unwanted material such as dirt, water, debris, animals, etc. from entering open ended pipes. This is critically important when protecting your expensive pipeline projects. These pipe plugs are composed of two steel "discs," which are compressed together by tightening the central bolt using the Special Expansion Plug Wrench. As the discs are compressed together, the rubber expands, ensuring a tight fit inside the diameter of the pipe. These detachable plugs offer a gas tight seal making it easy to change out a valve or fitting.