• Quality constructed from heavy-duty galvanized steel - 28 to 22 ga, depending on size with lightweight aluminum damper blades Used as a backdraft damper for heat exchangers, exhaust systems, solar heating systems and other intake or exhaust applications where a powered damper is not needed, this product is not rated for use with a dryer Works in both horizontal or upward air flow positions and the foam seal provides minimal air leakage Opens easily with normal air flow and closes with gravity, due to the specially designed angled aluminum damper blades Available for duct sizes ranging from 4 to 20 in

The Famco BD butterfly backdraft damper is used as a backdraft damper for heat exchangers, exhaust systems, solar heating systems and other intake or exhaust applications where a powered damper is not needed, this product is not rated for use with a dryer. This damper works in both horizontal or vertical positions and the foam seal provides minimal air leakage. Due to its unique design and aluminum blades, it opens easily with normal air flow and closes with gravity. Quality constructed from heavy-duty galvanized steel, sizes 4 to 6 in are 28 ga, sizes 8 to 12 in are 26 ga, size 14 in is 24 ga and sizes 16 to 20 in are 22 ga.