Abstract: An air-pressure applying assembly for a seat, having an occupant holding portion, for selectively applying a desired pressure to the body of a seat occupant. This assembly includes an air-bag assembly, an air-pressure source, an inlet-conduit assembly, an exhaust valve assembly, and a control assembly. The air-bag assembly is removably mountable to the seat occupant holding portion. The inlet-conduit assembly is in fluid communication at one end to the air-pressure source and at another to the air-bag assembly. The exhaust valve assembly is in fluid communication at one end to the inlet conduit assembly and has an air-outlet at the other end. A control assembly is linked to the air pressure source and to the exhaust valve assembly.