A patient interface assembly comprising: a patient interface comprising: a body and two nasal prongs extending from the body, each of the nasal prongs having a gas inlet for fluid communication with a supply of breathable gas, and a gas outlet configured to direct a flow of gas towards a nare of a user's nose, wherein each of the nasal prongs is in fluid communication with the other of the nasal prongs via a manifold, the manifold having a first opening and a second opening, and wherein: in a first configuration, the first opening is the gas inlet of the manifold and the second opening is the gas outlet of the manifold; and in a second configuration, the second opening is the gas inlet of the manifold and the first opening is the gas outlet of the manifold; each of the nasal prongs further including an exterior surface, at least a portion of the exterior surface is a sealing surface configured to seal the nare of the user's nose; and a securement system for the patient interface and/or patient interface tubing, comprising a bonnet, a two-part releasable attachment or connection arrangement, the arrangement comprising a first patch, and a second patch, the first patch has a patient side and an interface side, the first patch is attached to, or attachable to, the bonnet, or a headgear strap that is part of the securement system, the interface side of the first patch being provided with the first part of the two-part releasable attachment or connection arrangement, the second patch having an interface side and patient side, the patient side of the second patch being provided with the complimentary second part of the two-part releasable attachment or connection system, and the interface side of the second patch being attachable, connected to or formed as part of the patient interface and/or associated patient interface tubing. a patient interface comprising: a body and two nasal prongs extending from the body, each of the nasal prongs having a gas inlet for fluid communication with a supply of breathable gas, and a gas outlet configured to direct a flow of gas towards a nare of a user's nose, wherein each of the nasal prongs is in fluid communication with the other of the nasal prongs via a manifold, the manifold having a first opening and a second opening, and wherein: in a first configuration, the first opening is the gas inlet of the manifold and the second opening is the gas outlet of the manifold; and in a second configuration, the second opening is the gas inlet of the manifold and the first opening is the gas outlet of the manifold; each of the nasal prongs further including an exterior surface, at least a portion of the exterior surface is a sealing surface configured to seal the nare of the user's nose; and a securement system for the patient interface and/or patient interface tubing, comprising a bonnet, a two-part releasable attachment or connection arrangement, the arrangement comprising a first patch, and a second patch, the first patch has a patient side and an interface side, the first patch is attached to, or attachable to, the bonnet, or a headgear strap that is part of the securement system, the interface side of the first patch being provided with the first part of the two-part releasable attachment or connection arrangement, the second patch having an interface side and patient side, the patient side of the second patch being provided with the complimentary second part of the two-part releasable attachment or connection system, and the interface side of the second patch being attachable, connected to or formed as part of the patient interface and/or associated patient interface tubing.