Women's nylon hose or pantyhose works fine. If you're using discarded pantyhose, you may want to tie one of the legs into a knot, essentially turning it into a single hose, especially if one leg has a run in it. The bigger problem is how to attach it to the vent hood on the exterior wall. I've had success by driving four screws into the wall in a square arrangement around the vent hood and attaching two lengths of wire to the screws. You can use some #12 or #14 solid copper wire, or similar galvanized mechanic's wire. Wrap the wires around each screw head one turn so you end up with two vertical wires on each side of the vent hood, with the stubs projecting about an inch above and below the hood, like horns. Simply stretch the open end of the hose over the wire stubs to hold it snugly against the house wall. It is very easy to remove the hose for cleaning or replacement. With the dryer operating, the hose should not fully inflate, indicating there is sufficient area for the exhaust air to escape without appreciably increasing back-pressure, which could lead to the dryer overheating and shutting down.