Wind Noise Drivers Side mirror

Hi new here. I bought a 2014 sportswagen last month. I noticed when I get to around 65-70 on the interstate there is a whistling noise. Originally I thought it was the door trim. After some testing aka rolling down the window and moving my hand around. I found that covering the mirror base the whistling went away.
Flipping the passenger side window back shows some felt on the top of the mirror base. The driver’s side had some felt but mostly glue residue. Right now I have a pipe cleaner stuffed in the gap. Where can I find the felt? What is it called felt tape?

I was about to use some felt stickers from Hobby Lobby I used "PET Fleece Noise Damping Loom Wire Harness Cloth Electrical Tape" that I had in my tool bag. Haven't had any noise yet.

My 2011 had awful whistling from the drivers side mirror, I got some adhesive backed Velcro and used the loop side, worked great and the grey color I got was a pretty good match for the paint not a peep for over 100000 miles