A patient interface comprising a mask and headgear for securing the mask to a user's face, the headgear comprising an elastic portion configured to provide a retraction force, a non-elastic portion configured to be inelastic in comparison to the elastic portion, and a restriction mechanism connected to the non-elastic portion and to the elastic portion, the restriction mechanism configured to require a first resistance force to permit elongation of the headgear and having a second resistance force in response to retraction of the headgear,the restriction mechanism comprising a directional lock arrangement,the non-elastic portion comprising a core member and the elastic portion comprising an elastic strap,the core member being connected to the elastic strap and comprising a first portion, a second portion, and a portion passing through the directional lock arrangement,the elastic portion providing a force tending to move the core member through the directional lock arrangement,the headgear or the mask comprising a conduit or tube that resides in, is carried by, or is formed in the headgear or the mask respectively,the first portion being attached to a part of the headgear other than the core member or to the mask, and the second portion being a free end retained entirely within the conduit or tube.
