A tubing assembly for use with a patient interface device in delivering a flow of breathing gas to an airway of a user, the tubing assembly comprising: a manifold portion structured to be disposed generally atop the user's head and adapted to be coupled to a conduit carrying the flow of breathing gas; a plurality of tubular portions (120, 122) made from plastic and/or silicone, each tubular portion (120, 122) extending from the manifold portion to a distal end which is structured to be coupled to the patient interface device, each tubular portion (120, 122) being structured to communicate the flow of breathing gas from the manifold portion to the patient interface device; and, at least one adjustment unit (134, 136) configured to adjust a length of a corresponding tubular portion (120, 122) from the plurality of tubular portions (120, 122), wherein the at least one adjustment unit (134, 136) comprises a first adjustment member integral with or fixedly connected to the corresponding tubular portion and a second adjustment member integral with or fixedly connected to the corresponding tubular portion (120, 122), wherein the first adjustment member and the second adjustment member are movable relative to each other, and wherein the first adjustment member and the second adjustment member are selectively and releasably locked to each other at a selected discrete position from a plurality of discrete positions, the plurality of discrete positions corresponding to a plurality of predetermined lengths of the corresponding tubular portion (120, 122), characterized in that the at least one adjustment unit (134, 136) further comprises an adjustable section integral with the corresponding tubular portion (120, 122), wherein a relative movement between the first adjustment member and the second adjustment member causes the adjustable section to elongate or contract, and wherein the adjustable section is made from plastic and/or silicone. a manifold portion structured to be disposed generally atop the user's head and adapted to be coupled to a conduit carrying the flow of breathing gas; a plurality of tubular portions (120, 122) made from plastic and/or silicone, each tubular portion (120, 122) extending from the manifold portion to a distal end which is structured to be coupled to the patient interface device, each tubular portion (120, 122) being structured to communicate the flow of breathing gas from the manifold portion to the patient interface device; and, at least one adjustment unit (134, 136) configured to adjust a length of a corresponding tubular portion (120, 122) from the plurality of tubular portions (120, 122), wherein the at least one adjustment unit (134, 136) comprises a first adjustment member integral with or fixedly connected to the corresponding tubular portion and a second adjustment member integral with or fixedly connected to the corresponding tubular portion (120, 122), wherein the first adjustment member and the second adjustment member are movable relative to each other, and wherein the first adjustment member and the second adjustment member are selectively and releasably locked to each other at a selected discrete position from a plurality of discrete positions, the plurality of discrete positions corresponding to a plurality of predetermined lengths of the corresponding tubular portion (120, 122), characterized in that the at least one adjustment unit (134, 136) further comprises an adjustable section integral with the corresponding tubular portion (120, 122), wherein a relative movement between the first adjustment member and the second adjustment member causes the adjustable section to elongate or contract, and wherein the adjustable section is made from plastic and/or silicone.