A protective cowl designed to be attached on a gas cylinder, said gas cylinder having an upper part including a cylindrical neck with a thread around its lateral surface and whose top is equipped with a valve itself provided with a lateral opening, said protective cowl comprising an upper protective and handling component comprising:. a seat with a lower opening to enable the passing of the valve of the gas cylinder;. a vertical wall arranged on all or part of the periphery of the seat;. at least one lateral opening provided in the vertical wall; which further comprises: - a lower attachment component having a thread that matches the thread of the cylindrical neck of the gas cylinder and that is intended to be screwed thereon, and characterized in that said lower component comprises positioning structures in the form of vertical ribs which, in combination with the matching positioning structures in the form of vertical ribs of the upper component, are designed to enable the desired positioning of the lateral opening relative to the lateral hole of the gas cylinder valve, while preventing the upper component from rotating relative to the lower component when they are mutually engaged,. and in that a locknut having an opening that comprises a thread matching the thread of the cylindrical neck of the gas cylinder, this locknut being designed to be screwed onto the thread of the gas cylinder so as to fit the seat of the upper component tightly around the lower component, the locknut having a toothed ring arranged on its lower side around its opening and which engages with a matching toothed ring provided on the upper perimeter of the opening of the lower component.. a seat with a lower opening to enable the passing of the valve of the gas cylinder;. a vertical wall arranged on all or part of the periphery of the seat;. at least one lateral opening provided in the vertical wall; which further comprises: - a lower attachment component having a thread that matches the thread of the cylindrical neck of the gas cylinder and that is intended to be screwed thereon, and characterized in that said lower component comprises positioning structures in the form of vertical ribs which, in combination with the matching positioning structures in the form of vertical ribs of the upper component, are designed to enable the desired positioning of the lateral opening relative to the lateral hole of the gas cylinder valve, while preventing the upper component from rotating relative to the lower component when they are mutually engaged, - a lower attachment component having a thread that matches the thread of the cylindrical neck of the gas cylinder and that is intended to be screwed thereon, and characterized in that said lower component comprises positioning structures in the form of vertical ribs which, in combination with the matching positioning structures in the form of vertical ribs of the upper component, are designed to enable the desired positioning of the lateral opening relative to the lateral hole of the gas cylinder valve, while preventing the upper component from rotating relative to the lower component when they are mutually engaged,. and in that a locknut having an opening that comprises a thread matching the thread of the cylindrical neck of the gas cylinder, this locknut being designed to be screwed onto the thread of the gas cylinder so as to fit the seat of the upper component tightly around the lower component, the locknut having a toothed ring arranged on its lower side around its opening and which engages with a matching toothed ring provided on the upper perimeter of the opening of the lower component.