A respiratory pressure therapy system comprising: a plenum chamber pressurisable to a therapeutic pressure of at least 6 cmH 2 O above ambient air pressure; a seal-forming structure constructed and arranged to form a seal with a region of the patient's face at or surrounding an entrance to the patient's airways such that a flow of air at said therapeutic pressure is delivered to at least the entrance to the patient's nares, the seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; a positioning and stabilising structure constructed and arranged to provide an elastic force to hold the seal-forming structure in a therapeutically effective position on the patient's head, the positioning and stabilising structure comprising a tie, a lateral portion of the tie being constructed and arranged to overlie a region of the patient's head superior to the otobasion superior in use, and a superior portion of the tie being constructed and arranged to overlie a region of the patient's head in a region of the parietal bone in use, wherein the positioning and stabilising structure has a non-rigid decoupling portion; a blower configured to generate the flow of air and pressurise the plenum chamber to the therapeutic pressure, the blower having a motor, the blower being connected to the plenum chamber such that in use the blower is suspended from the patient's head and an axis of rotation of the motor is generally perpendicular to the patient's sagittal plane; and a power supply configured to provide electrical power to the blower. a plenum chamber pressurisable to a therapeutic pressure of at least 6 cmH 2 O above ambient air pressure; a seal-forming structure constructed and arranged to form a seal with a region of the patient's face at or surrounding an entrance to the patient's airways such that a flow of air at said therapeutic pressure is delivered to at least the entrance to the patient's nares, the seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; a positioning and stabilising structure constructed and arranged to provide an elastic force to hold the seal-forming structure in a therapeutically effective position on the patient's head, the positioning and stabilising structure comprising a tie, a lateral portion of the tie being constructed and arranged to overlie a region of the patient's head superior to the otobasion superior in use, and a superior portion of the tie being constructed and arranged to overlie a region of the patient's head in a region of the parietal bone in use, wherein the positioning and stabilising structure has a non-rigid decoupling portion; a blower configured to generate the flow of air and pressurise the plenum chamber to the therapeutic pressure, the blower having a motor, the blower being connected to the plenum chamber such that in use the blower is suspended from the patient's head and an axis of rotation of the motor is generally perpendicular to the patient's sagittal plane; and a power supply configured to provide electrical power to the blower.