4'' Inch duct connector with mounting plate. PVC plastic flange for flexible or straight pipe. Plastic pipe connector of round ducts and cover plate. Perfect for HVAC systems. - - Amazon.com
Ventilationsrør, Duka - dba.dk - Køb og Salg af Nyt og Brugt
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HVAC OV 6" inch Plastic Straight or Flexible Pipe Flange for Extraction Fans, Heating and Cooling Duct Connection. Round Duct Connector Flange - - Amazon.com