A piston for an internal combustion engine may include a piston head and a piston skirt. A plastic outer shell has a base wall with a peripheral skirt and a plurality of internal L-shaped lugs at a juncture of the base wall and the peripheral skirt. The thin barrier membrane comprises a thickness operable to maintain the weight distribution of a patient on the weight bearing upper surface of the resilient medical patient pressure redistribution support substantially the same compared to the weight distribution without the thin barrier membrane. The extension members may be attached to conversion enabling structure on the pallet surface components to assemble a selected piece of equipment. Thus, a deep trench arrangement can be achieved without being restricted by the overall width of the isolation structure.