Flex duct is not supported at Revit Fabrication

[sujay.nathN59LG]

Unable to draw flex duct at revit fabrication. When I try to draw flex duct it shows This content is not currently supported. Kindly help me if anyone know how to solve this issue.

[MOatman]

You have to use the Flex Duct button under the Systems Tab.  For Equipment, you have to use Families.