Abstract: A valve for controlling fluid flow is disclosed in which a fluid outlet is controlled by two separate components, one being tubular in shape and located inside the other hollow component. Both the hollow and the tubular components may either be the valve body and closing element respectively, or vice-versa. The two components are reciprocally slidable through elastic sealing rings along their common longitudinal axis, and are also rotatable about that same axis, whence the path of fluid flow may be readily controlled in a gradual manner from the fully shut position to the fully open position, depending upon the longitudinal position of a plunger element with respect to the valve body. The plunger is in a state of static balance with respect to any existing pressure or friction, as well as with respect to its own weight.