diesel heater vent duct flange

The piece that came with my Chinese diesel heater wasn't long enough to go through the floor of my camper and leave enough room to clamp onto so I designed this. It isn't perfect as the spacing of the grids isn't even but hey it works and I was in a hurry since it is about to get super cold outside. I hope that this can help anyone else that had the same problem I did. I made two versions, depending on what type of filament you use the file with the taller cross members may be helpful to strengthen it and fight the warpage from the heat.