This may help:
http://www.thermaflex.net/thermaflex.php This is the brand that is used in my rig.
I pulled the manufacturer's sticker off of a run of the foil stuff in our TT, and it states "FOR INSTALLATION IN LENGTH NOT OVER 14 FEET."
The online spec sheet for the foil stuff doesn't really give a max. length limit, but does say the stuff comes in 25' pieces.
The spec sheet for the gray stuff specifically says it's not limited in length of use like the foil stuff. Guess that means it is good for longer runs as in your TT's. Probably costs more, too.
Neither are insulated. Both are spec'd from -20 F to 250 F. They specifically mention residential bathroom vent runs in the product sheets so I am pretty sure this is the exact same stuff you'd buy at Home Depot, etc. for bathroom vents or dryer vents.
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'12 F250 4x4 Super Duty PowerStroke 6.7 diesel
2011 to present: '11 Cougar 326MKS
1999 to 2011: '99 Sunline T-2453
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