A mask assembly adapted to facilitate the delivery of a supply of air or breathable gas to the entrance of the airways of a patient, comprising a foam-based interfacing structure (x30) comprising a cushioning component (x32) and a clip portion (x34) configured to attach the cushioning component to a frame; wherein at least a first region of the cushioning component (x32) comprises a generally triangular cross-sectional profile having three sides: an inner side which faces into the centre of the mask assembly , an outer side which faces away from the center of the mask assembly and a base surface adapted to be joined at least in part to the clip portion (x34); wherein an interior of the interfacing structure at least partially forms a cavity to receive at least a portion of the patient's nose in use; wherein the interfacing structure (x30) in the first region is characterized by at least one of the following: 1) the clip portion (x34) is mounted proximal to the outer side of the cushioning component (x32) and provides little or no support relative to the inner side of the cushioning component (x32) to allow the cushioning component (x32) in the first region to roll inwards and 2) the clip portion (x34) is joined to the cushioning component (x32) by an upper side, wherein the upper side is angled towards the centre of the mask assembly to allow the cushioning component (x32) in the first region to roll inwards. a foam-based interfacing structure (x30) comprising a cushioning component (x32) and a clip portion (x34) configured to attach the cushioning component to a frame; wherein at least a first region of the cushioning component (x32) comprises a generally triangular cross-sectional profile having three sides: an inner side which faces into the centre of the mask assembly , an outer side which faces away from the center of the mask assembly and a base surface adapted to be joined at least in part to the clip portion (x34); wherein an interior of the interfacing structure at least partially forms a cavity to receive at least a portion of the patient's nose in use; wherein the interfacing structure (x30) in the first region is characterized by at least one of the following: 1) the clip portion (x34) is mounted proximal to the outer side of the cushioning component (x32) and provides little or no support relative to the inner side of the cushioning component (x32) to allow the cushioning component (x32) in the first region to roll inwards and 2) the clip portion (x34) is joined to the cushioning component (x32) by an upper side, wherein the upper side is angled towards the centre of the mask assembly to allow the cushioning component (x32) in the first region to roll inwards. 1) the clip portion (x34) is mounted proximal to the outer side of the cushioning component (x32) and provides little or no support relative to the inner side of the cushioning component (x32) to allow the cushioning component (x32) in the first region to roll inwards and 2) the clip portion (x34) is joined to the cushioning component (x32) by an upper side, wherein the upper side is angled towards the centre of the mask assembly to allow the cushioning component (x32) in the first region to roll inwards. <EOS>