What I used is similar to those. It was some leftovers from a big rig shop. They use it on flatpanels to stop them from flexing and vibrating. It has aluminum backing and what looks like tar to makeŽem stick. Smells bad but the smell fades fast.

ya thats what im talking about the stuff iv used didn't even smell bad to begin with, but it works just like dynomat, i put a whole crap load of that in my buddies 86 runner when we put his system in and it made a huge difference. and its not called that, i actually don't know what its called.. but they use it with roof flashing applications.