Rubber-Cal Closed Cell Sponge Rubber Neoprene 5/8 in. x 39 in. x 78 in. Black Foam Rubber Sheet 02-128-0625 - The Home Depot
Closed cell foam vs open cell foam
Amazon.com: 2 Roll Neoprene Sponge Foam Rubber Sheet Foam Closed Cell Soundproof 3/8" T x 13" W x 80" L Cosplay Padding Multi Function Mat Non Adhesive Easy to Cut for DIY
Closed Cell Foam: Types, Applications, Benefits, and Manufacturing