Abstract: An actuator for releasing a pressurized fire extinguishing composition from the cylinder of a fire extinguisher has an elongated body made of a single piece. The body has a longitudinal chamber that extends through it for holding a ram that moves along the chamber and a spring for propelling the ram, a first transverse aperture for holding a trigger that releases the spring and a second transverse aperture for holding a member that moves due to movement of the ram, where both apertures join the chamber. Movement of the member releases the composition from cylinder. A microswitch or a cable, activated by the ram, may be attached to either or both ends of the chamber.