Pneumatic apparatus is disclosed for installing a garbage disposer under a kitchen sink which comprises a base structure and an inflatable, air-tight bellows which is attached to the top of the base structure. A device is presented comprising: at least one partition body; at least one motility assembly operably adapted to at least one partition body; and at least one interconnect, where the at least one interconnect is used to interchangeably link the at least one partition body in multiple configurations with another partition body. This new relative permeability model maintains the physical consistency in the transition from Type II to Type III to Type II systems and vice versa. A region of the outer part of the exchanger includes a planar portion on one of both sides of the exchanger. Seating areas for positioning horizontally andor vertically disposed rebar in predetermined positions are also provided.