They do a great job of cover the vent holes under the seats. It was difficult getting the tape to stick. I sure alcohol to clean the vent and it still seemed like the cover wanted to come off.
When I recently saw that Tesmanian is selling floor vent covers for the Tesla Model Y I immediately purchased a set as I was confident that the Tesmanian floor vent covers for the Model Y would fit well, I was not disappointed. As noted by another reviewer the vent covers did not come with instructions. After testing the fit was clear that the vent covers only fit the floor vent opening with the thicker edge of the floor vent cover oriented at the bottom. There is a thin strip of double sided automotive trim tape on back on three sides of the vent cover. Installation was easy, I am very satisfied with the floor vent covers for the Model Y.
There was not instruction how to install the covers so just installed it as I see how it should go. Hopefully it is correct.