Abstract: An apparatus is disclosed for selectively adjusting the firmness of various surface regions of a mattress, including regions providing lumbar, thoracic, and pelvic support to a user. The mattress comprises a plurality of removable tubes filled with a variety of materials, which tubes are inflatable and deflatable by a compressor operating in accordance with the programming of a user. The user is supported on the mattress by, inter alia, the removable, subsurface, tubing which is pressurized by its hybrid material-air contents.