A pillow system configured to engage the back and sides of a subject's head, the pillow system comprising: a cushioning material (45, 50, 55) configured to engage the back and sides of the subject's head responsive to the head of the subject being in place on the pillow system; a resilient frame configured to surround the back and sides of the subject's head to hold the cushioning material in place on the subject's head, the frame comprising: a first portion having a first inner side and a first outer side, the first portion being configured to hold the cushioning material in place on a first side of the subject's head responsive to the subject's head being in place on the pillow system; a second portion having a second inner side and a second outer side, the second portion being configured to hold the cushioning material in place on a second side of the subject's head responsive to the subject's head being in place on the pillow system; an adjustable portion at a location proximate to the back of the subject's head that connects the first portion and the second portion, the adjustable portion providing adjustment to move to and retain spacing between the first portion and the second portion to accommodate differences in distances between the first side of the head and the second side of the head for different subjects; and a tube adapted to deliver breathable gas to a mask, wherein the tube is attached to the first inner side, the first outer side, the second inner side, or the second inner side. a cushioning material (45, 50, 55) configured to engage the back and sides of the subject's head responsive to the head of the subject being in place on the pillow system; a resilient frame configured to surround the back and sides of the subject's head to hold the cushioning material in place on the subject's head, the frame comprising: a first portion having a first inner side and a first outer side, the first portion being configured to hold the cushioning material in place on a first side of the subject's head responsive to the subject's head being in place on the pillow system; a second portion having a second inner side and a second outer side, the second portion being configured to hold the cushioning material in place on a second side of the subject's head responsive to the subject's head being in place on the pillow system; an adjustable portion at a location proximate to the back of the subject's head that connects the first portion and the second portion, the adjustable portion providing adjustment to move to and retain spacing between the first portion and the second portion to accommodate differences in distances between the first side of the head and the second side of the head for different subjects; and a first portion having a first inner side and a first outer side, the first portion being configured to hold the cushioning material in place on a first side of the subject's head responsive to the subject's head being in place on the pillow system; a second portion having a second inner side and a second outer side, the second portion being configured to hold the cushioning material in place on a second side of the subject's head responsive to the subject's head being in place on the pillow system; an adjustable portion at a location proximate to the back of the subject's head that connects the first portion and the second portion, the adjustable portion providing adjustment to move to and retain spacing between the first portion and the second portion to accommodate differences in distances between the first side of the head and the second side of the head for different subjects; and a tube adapted to deliver breathable gas to a mask, wherein the tube is attached to the first inner side, the first outer side, the second inner side, or the second inner side.