Abstract: A screw-less batten system is described. The screw-less batten system includes a stud, at least one removable flange and at least one closure strip. The stud includes a neck opening with at least one receiving trough. The stud also includes a jamb-nut channel. The jamb-nut channel has a predetermined profile. In some embodiments, the screw-less batten system includes a jamb-nut.

Abstract: The present invention relates to a flow rate adjustment device which allows for adjustment of air flow through the fan without changing the rpms of the fan blades. In one embodiment, an adjustable plate is located in the center of the impeller and is movable in such a manner that various lengths of the blade edges are blocked from the intake air at the center of the impeller. In another embodiment of the invention, the plate is replaced by an inflatable blocking device which can be inflated to various degrees thereby blocking various lengths of the blade edges. In both embodiments, the blocking of the blade edges results in less intake air being exposed to the blades, and thus less air moves through the fan even though the rpms remain constant.