3 Black Square Head Cored PlugThe 3 Black Square Head Cored Plug is a threaded pipe fitting used to seal the end of a female threaded pipe or fitting. The square head design allows for easy tightening and removal using a wrench or socket tool. The cored (hollow) design, reduces material weight while maintaining durability. This plug is commonly used in plumbing, gas, oil, and air systems to close off pipe openings, ensuring leak prevention and system integrity. Specification