This invention relates to a patient interface (88100) for delivering a supply of gases to a patient, comprising a gas supply manifold (88110) for receiving and directing to an outlet or outlets to a patient a gas supply, and a pair of elongate side arms (88113, 88114) extending from opposite sides of the manifold to contact a user's face in use to aid in stabilising the interface on the user's face, each of said side arms comprising a part twisted portion, such that a cross-section shape orthogonally through the side arm is part twisted anti-clockwise or clockwise at a part of the side arm closer to an outer end relative to a part of the side arm closer to the manifold, the twist being when considered from a top or bottom view of the interface and said respective side arm(s).
