Product review (2 stars): Thin, Flimsy, and Leaks
Plastic is very, very thin. The air easily escapes on the sides bottoms (I don't know why the V shape lips. It's for stabilizing the sliding part, it does nto do the job). The extension part is very loose if you extend until the very end to get the max length. I had to tape the entire vent to the ground to avoid leaks and stabilize it on the floor. When the air is finally out (in my case) it is much colder/warmer due to the loss of temperature along the vent.