Hi All.... did you know that Mc Master Carr sells our most favorite toroid material in 16" diameters? the aluminim flex duct hose onlly problem is that it costs 25$ per section ( supposedly streaches to 8' but i could only get 5' ) im on break right now but im working on my new 16" X 62" toroid for my 12"x50" coil its huge !!!! :) Scot D