I typed a fib, LOL. It is a K&S product and not Great Planes. Here's the link.

http://www3.towerhobbies.com/cgi-bin...LXYE85&P=0

Yes it is vary flexible! I took a tank apart that I had it in after a season of use and it was still just as flexible as the day it was installed. It looks and feels like the same stuff that they use on weedeaters or other 2stroke garden tools.