It is as thin as a windbreaker, lets the wind through. Doesn't work at all on ice and snow. The flaps, which are designed to protect the car from theft, slide out without much effort when the door is closed. Mine came out when I inserted the second flap in the other door. It was uncomfortable, like trying to put a sheet on the mattress and it kept bouncing off the other side. When it started to snow I went to take the blanket off and it was half off. So what was the point? The half that stayed in the car froze to the car.