The butterfly damper has a built-in virtually airtight permanent gasket and can be used in residential and commercial ventilation systems. According to the manufacturer, the nearly 100 percent efficient performance of the butterfly damper also helps prevent off-season condensation. Available in the MV and GRD series diffusers, the durable polymer damper features a rubber gasket that, when shut off, allows virtually no air passage, according to airflow tests. The patented butterfly damper comes with an easy-to-adjust worm gear mechanism. An accessible handle allows hand adjustments, or it can be removed in public areas to provide authorized access only with a flat-blade screwdriver. The unit is available in two sizes for the 6- and 8-inch MV Series of ceiling diffuser, and 8-inch for GRD Series diffusers.

Airtec Products Corp., 1244 Davol St., Fall River, MA 02720; 800-324-7832 or 508-675-2669;;

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