Storystore Foam Insulation Neoprene Sheets with Adhesive, 1/2'' Thick x 12'' W x 59'' L Multi-Function Soundproof Large Closed Cell Neoprene Rubber Roll, White

It worked well for sealing the holes and gaps around the window unit. It is thinner than I expected but it does what it claims it does.

Buen producto, pero excesivamente caro ...

I covered up the crawlspace vents with this, and it was easy to cut and put into place to seal them up and keep the cold out

It does NOTHING for sound blocking or sound deadening door panels. Neoprene is a great thermal insulator, it sticks very well. Thermal insulated exposed metal on the firewall .. car stays much cooler in the summer, holds heat in the winter.I glued it over 50mil Butyl mat that actually deadens engine / road noise.

Bought this to cover the outside of an insulated portable air conditioner panel that faded to yellow and was unsightly. Scissor cut and stuck on the cleaned existing mess. It's been install for a month, thru rain, wind, and bright sun. Looks like I just installed it. Very happy with purchase.