A mask system for delivery of respiratory therapy to a patient includes a nares portion and a mouth portion and an inlet conduit connected to at least one of the nares portion and the mouth portion to deliver the pressurized, breathable gas. The mask system is adapted to selectively utilize the nares portion and/or the mouth portion in a first mode utilizing both the nares portion and the mouth portion, and in a second mode utilizing the nares portion and not utilizing the mouth portion.