2.5 inch air hose ducting. Made by Porterfield. Used for the heating system in the engine bay as well as the short pieces from flapper boxes to the heat exchangers.

I have a 4 foot section left over. $40 plus shipping.

http://www.porterfield-brakes.com/pr...p?productID=19

The Silicone has a max heat temp of 600F, they are sold in 11 foot sections. They are designed for moving air from a wide temp range, they are lightweight and extremely flexible. Made with fiberglass cord and bronze plated steel spring wire helix.

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