If anyone is interested I figured it out. Its rigid insulation foam. The best one to use is foamular 1000 R7.5 1 1/2 inch. You can cut your own squares out and drill your own holes for cheap.
Thanks for the input. I have tried most of the mentioned options. Seems like each company has a few duds mixed in with surprisingly decent frames in this pricing tier.
So, what is your feedback about the quality!?
So, what is your feedback about the quality!?
misha.misha 12-15-2019, 04:10 PM