Trickle ventilation extractor cowl

I didn't want to drill a hole in the wall for fume extraction from my printer enclosure so this cowl allows a double glazing trickle vent to be used as the outlet. It doesn't damage the window frame which is useful if you don't happen to own the room you are in. The pipe is a PU Flexible Ducting Hose, 50mm ID, which is widely available.
There are two cowl designs a plain and a longer one with a rim at the bottom. The length doesn't matter because you will need to split the print for most printers and at that point you can make more centre sections to adjust the length to that required. The set of parts is then glued back together. The lipped design is to provide a surface for double sided tape to attach the cowl to the frame surface below the vent.
I have also uploaded a 50 mm bulkhead fitting for the enclosure that is sized for a 40 mm axial fan. If I did this again I would probably go up a fan size (maybe 80mm) as the 40 mm produces only a small flow down about 3 m of pipe.