Spiral and Doublewall 

Cut corners for a newer standard for duct in the industry. Nothing makes better airflow than round pipe!
Closed cell liner is an expandable foam insulation that needs little or no glue to install. Double wall pipe and fittings can be made in house using a sharp knife to cut it, or a router.
All made possible by my co worker. I couldnt run spiral pipe if I tried.
Song Credits - Lurkin by basskaT //// B-Boy Theme by Emapea