reflextics - well the shiny bubble wrap type stuff

[sternwake]

If gravity is causing a sag, try taping something stiffer in the middle of the reflectix. I used some ~22" x 1.5" x 1/8" white oak strips on the very edges that I had left over after making something custom using my table saw, and the center of the reflectix windshield shade has some super stiff non corrugated cardboard preventing it from creasing in the middle.

My drivers and passenger door panels are slightly oversized, and I left some flexfix tape beyond those perimeters that I can put a magnet on top of, and no way could the panel then move.

Always try and roll or crease the reflectix in the same manner. Developing a system will occur without trying, but trying to develop a system / rolling unrolling habit right off the bat can make setting up the front window shades a 20 second task rather than a 3 inute curse fast..

While this all adds weight and bulk, the visors alone are enough to keep it tight to my windshield with very little light escaping the corners.