SummaryThose dang Possums kept knocking out my roof vents and living inside our roof. They made lots of noise getting inside, waking us up at 4am - now they don't - I built them a Possum house and inside the roof is off limits. My Vents also include 3D printed flywire - to keep any smaller flying buggy pests away They are held in place by (3D printed) clips at each end, and two 3D printed Joiners in the center. Also, we have an older house, and I couldn't find any Imperial measurement replacements The vent size is 201mm X 104mm To install, push one 3D printed vent into the roof, screw in both joiners, then push in the other one and screw tight.