looking for insulation

was looking for insulation,seen on tv I think was called dura skin or something like that.Do I have to put underlay on top as well when putting carpet on

I found it,is called dynamat

dynamat is the best out their period, after you install the dynamat install dynapad you will not get any road noise at all, you can order dynamat threw the INTERIOR SHOP @ 602-548-0059 Bulk Pack of dynamat is 189.-- it has nine full sheets