Abstract: A spacer system of variable height comprises two longitudinal upper members and three transverse lower members. Each of the longitudinal and transverse members includes plural groupings of adjacent slots of varying depth. The upper longitudinal members each have three spaced apart groupings of adjacent slots with two slots of varying depth in each grouping while the transverse lower members each have two groupings of adjacent slots with three slots of varying depth in each grouping. The slots in the upper longitudinal members open in a downward direction and interlockingly and releasably engage the slots in the lower transverse members which open in an upward direction. Variable height of the spacer system depends upon which slot of each grouping in the longitudinal members interlocks and releasably engages a given slot of each grouping in the transverse members.

Abstract: A flexible, resilient, annular grommet, preferably flanged at both ends, mounts to a circular hole within a planar generally rigid backing member. The backing member forms with a thin flexible sheet member having at least a portion underlying the backing member, a plenum chamber. The flexible sheet bears perforations to provide an air bearing with an underlying support surface for a load borne by the backing member. The grommet lower flange is bifurcated and separated circumferentially by radial slots to permit lateral escape of the air to the interior of the plenum chamber with the inner flange functioning as air dispersion means within the plenum chamber to insure air flow throughout the chamber when the pallet is under load. A cross-piece or its equivalent, borne by the grommet, functions as a mechanical lock when engaging a rigid air supply tube or nozzle at the end of an air inlet hose, for feeding air under pressure to the plenum chamber.