Abstract: An adjustable louver includes a longitudinally spaced pair of side frame numbers, a spaced apart pair of end members extending between the side members and including inner and outer submembers slidably engaging to extend or telescope through a continuum of positions respecting one another and blades extending between the side members with each blade including blade members which slidably engage to extend substantially through the continuum of positions through which said end members are extendable.

Abstract: A smoke damper which includes a rectangular frame and blades mounted in the frame such moveable between a position in which all of the blades are essentially coplanar with adjacent edges of adjacent blades being contiguous one with another, and a position in which the blades are rotated 90 degrees from the previous position with individual blades in planes parallel one with another. At least one of the blades has a recess formed along the length of the blade surface proximate to an edge of the blade and an elastomeric gasket mechanically secured to the edge of the blade having the recess which extends part-way across the recess from the edge of the blade towards the blade central portion.