5A is a perspective frontal view of the user interface unit of FIG. 5; FIG. 5B is a cross sectional view along line B-B of FIG. 5A; FIG. 5C is an exploded view of the encircled area of FIG. 5B; FIG. 6A-6C are frontal, profile and rear views, respectively, of an air delivering user interface unit in accordance with another embodiment of the invention; FIGS. 7A and 7B are a perspective view and expl