A face shield, patient interface and methods of use thereof are described for improved respiratory therapy of patients. In particular, a face shield is disclosed that acts as a seal when used with a patient interface. The face shield may be manufactured from a low melt temperature hard thermoplastic material. The face shield may be formed initially formed to match the general contours of the face, but not customised to a specific user's face. The face shield may be crosslinked to provide shape memory to the seal and to improve its handling properties and is configured to be thermoformed to a user's face. The face shield may be customised to the patient's facial features to a second customised shape.