I made this adapter while installing the ventilation hose for my Chinese K40 laser cutter. I have a squirrel cage fan that utilizes a 6" foil vent pipe, and none of the options available publicly were for this size. Everyone else was using 4" and 5" maybe with adapters of some sort. So in order to not limit air flow, I made an adapter that is direct, and should have enough of a lip on it to clamp down a hose. I have included STL, STEP, IGES, and Solidworks 2014 source files so any modification can be done should you need it.