I figured I would give this product a try. I typically cover all openings no matter how small with “rope’ type caulking. It does a pretty good job but I also wanted to use this product to insert over the extendable sides for added insulation. I kept the extendable sides of the A/C installed, filled all gaps with the rope caulking then inserted the foam product over the extendable side for added insulation. I did not have to use the tape fastener that came with the product. I simply cut to size and tucked in between window side and A/C. Looks great and I like. I ordered another set for my other bedroom window. I’m not sure how this product would work or hold up if used instead of the extendable sides. So for my application, I am very satisfied.






