Airtight backdraft dampers are designed to automatically shut off the air ducts when the fan is turned off . The NER-KO backdraft dampers are of gravity action type and designed for operation in high-pressure ventilation networks under conditions of sudden jumps of operating pressure in the network, as well as for sealing the internal volume of ventilation networks. - NER-КО dampers are unique for the domestic market, no comparables are observed.

They are made of both rectangular and round cross-sections.

Design: