Wynn Environmental has 25 mil thick 6" flexible hose that is used by ClearVue with their cyclones. It runs $46.00 per 10 foot length plus shipping. I bought a 25' length of the 6" economical clear PVC duct hose from McMaster-Carr for about $65 plus shipping -- it has 15 mil walls and is plenty heavy. I purchased 6" wire hose clamps for $0.95 each from William J. Redmond Machinery -- cheapest price on the planet. Hope this helps.
I have both types that Rob cites. As long as you are not moving it around or run it where you might step on it, the lighter McMaster-Carr stuff is fine. MMC ships quickly from Atlanta.