Abstract: A fire extinguisher which maintains a constantly high pressure inside a shell of the fire extinguisher through out a shelf-life of the fire extinguisher comprising an ejection chamber having internal threads at its lower edge and a shell having external threads at its upper edge to mate tightly with internal threads of ejection chamber where shell contains fire extinguishing agent in an absolutely closed system, and where there is a pressing element presses on top of a plate fillet welded to an inner lower wall of the ejection chamber. Upon destroying pressing element, pressure inside shell causes a hole being formed in said plate allowing ejection of fire extinguishing agent to put out fire.