Hose Adapters

Hose adapters are used to connect the duct to flex hose.

One end of the adapter is typically rolled-lip and the other end is a raw end (approximately the size of the inside diameter, ID, of the hose) with an expanded bead knurled onto the adapter end—allowing 2" of adjustability. 

A worm clamp is used to tighten the hose to the adapter and the expanded bead keeps it from sliding off.