HFC Enterprises Inc's DuraFlange and DC ring set is an efficient, rigid and lightweight oval and round duct connector designed to minimize installation times and maximize efficiency of an HVAC system. The wire rod designed into the perimeter of the DuraFlange duct connector reinforces even the lightest gauge spiral duct, increasing the structural integrity of the duct section and making it easy to handle and install. The DuraFlange system not only provides contractors with a quick, easy and cost effective way to connect ductwork, but it provides energy conscious engineers and developers a leak free HVAC system. The Duraflange oval, round and DC Ring Set's have all been tested to +/-10 W.G with virtually no leakage. The DuraFlange was designed with the end user in mind.