Defrost Duct Hose

Not sure if your looking for OE but this is where I bought mine from.

http://nostalgicac.com/duct-hose-vents/duct-hose-and-vents.html

I ordered 3 feet of the DH20, 3 feet of the DH25 and 1 of these.

http://nostalgicac.com/duct-hose-vents/duct-hose-adapters/2-inch-to-2-5-inch-duct-hose-adapter.html

Works good!