O.K., per your request, here are the pictures of my SR20 ventilation fan. (click here)
The gizmo is a 1-1/2 inch diameter, 50 milliamp, 12 volt DC CPU cooling fan, mounted on a 2 inch to 1-1/4 inch schedule 40 PVC pipe adapter fitting. The inside of the small end of the fitting is lined with felt to make a snug seal on the “eyeball” air outlet vent (it will fit any of the 4 air vents). The big end of the fitting has 4 triangular notches, the depth of the fan, cut out of its periphery to accept the 4 corners of the fan so the fan fits flush in the fitting. The fan is glued into the end of the fitting using silicone caulk. Make sure you mount it so the air blows OUT of the fitting, not into it! (I painted the outside of the fitting to match the fan, just so it would look tidy.) The fan is connected to a 12 volt, 125 milliamp solar panel array (one of those sold as “trickle chargers” for boats, RVs, etc.), which sits on top of the instrument panel when in use. (I put two strips of the “sticky” 1/2 of velcro on the back of the panel - when not in use, I just hang it on the carpet on the back wall of the luggage area. The fan and its cord go into the luggage door pocket.
Hope this is what you wanted to know!
P.S. Sorry about the overall picture quality - I had to compress the snot out of the images to get the overall picture down to a manageable size…