An adjustable mask apparatus for use in a breathing assistance system may include a housing, an adjustment arm, and a locking member. The housing may support a cushion configured to provide a seal against a patient's face. The adjustment arm may include a first end configured for attachment to a head gear, and a second end rotatably coupled to the housing to allow rotation of the adjustment arm to adjust a distance between the first end of the adjustment arm and the patient's head. The locking member may be coupled to the housing and may be configured to secure the adjustment arm in one of a plurality of predetermined rotational positions, each predetermined rotational position comprising a rotational position of the adjustment arm with respect to the housing.