Summary: layer of sound blocking material I also thought i would have a hard time cutting the stuff but with a razor blade knife it cut extremely easily I did not glue down the insulation The 3m Spray glue This dries enough to hold quickly enough that i was able to pull the fabric on the panels when I put on the burlap without any use of staples etc to hold it in place
Image Dimensions: 506 x 675
Image originally found here.