air duct enters compressed; in this state it is quite rigid. I tried to lengthen it to 8 feet (that's the spec length) by carefully spreading the ends. It stretched to 80 inches (or 6 ft 8 inches) with no damage, but wasn't stiff at all at 80 inches. It is no more rigid than foil packaging. When I tried to extend it past 80 inches, it just snapped, or "unwound," as another reviewer politely pointed out. This "unwinding" is irreversible, so this duct had to be discarded. Now I'm looking for another 5" x 8" flexible pipe.