Abstract: This disclosure provides a directional adjustment unit for a headgear for a respiratory mask The directional adjustment unit provides an increased resistance to extension of one or more straps of the headgear when the headgear is under tensile forces, as compared to a lower resistance to retraction of the one or more headgear straps. The directional adjustment unit comprises a movable frictional engagement member comprising an aperture, wherein the aperture is arranged to receive a filament of a strap of the headgear therethrough, wherein the frictional engagement member in a first configuration provides a disengaged or pre-activated configuration with respect to the filament, and in a second configuration provides an engaged configuration with respect to the filament. Features are provided which improve the operation of such a directional adjustment unit.