A patient interface gas delivery mask having a rolling diaphragm that connects a seal member forming a cushion which contacts the patient's face with a mask shell or that connects a conduit coupling member with the mask shell. The rolling diaphragm of the present invention allows the cushion to self align to the patient's face and allows relative movement between the seal member and the mask shell. This prevents torque acting of a conduit coupled to the mask shell from being translated to the seal member, which might otherwise dislodge the seal member creating unwanted gas leakage at the seal member-patient interface.