Abstract: An inflatable seat unit having a plurality of air cells positioned longitudinally adjacent to each other and fully contained within a cavity in a piece of foam material, the cells being covered by a portion of the foam material to form a seat surface, the portion having a thickness which permits the rise and fall of the air cells to be felt by the occupant of the seat, a back plate for supporting the cells and causing the cells to rise in the direction of the portion of foam material, and a control mechanism for admitting air into the air cells in a controlled manner and fully contained within said piece of foam material and rigidly secured thereto, said control mechanism having a rotating valve which is forced against the valve openings by pressurized air introduced to one side of the valve during rotation.