Bogdanov's nut with an internal thread is designed to connect different parts of fire fighting equipment. Thus, its use makes it possible to create a sealed pipeline, through which water or a special solution is supplied in order to eliminate fires. The design of a Bogdanov nut with a female thread is simple and reliable, therefore, creating a connection with its help is very fast and does not cause any difficulties for the persons performing it. This work is done manually, the usual manual effort is sufficient to ensure the tightness, and the use of additional equipment is not required. Bogdanov's coupling nuts have a number of advantages, the main of which are: • High reliability, which has been repeatedly confirmed by the manufacturer during field and bench tests. • Ability to withstand high internal pressure. • Anti-corrosion resistance achieved due to the fact that the sleeve is made of aluminum. Internal thread - 2 "