This pad has just enough supportive squish and thickness to help with 1/32 inch variations in subfloor, by my estimation.
It's comparable in function and probably insulative break to a quarter inch roll of natural cork. The two foot by 3 ft pieces fit together well, I taped some of the seams to aid in installation. Cutting with a razor knife or heavy duty scissors is very easy. I think this underlayment really facilitated the use of the warmly yours radiant heat mat on top. I appreciate that it provides a thermal break between the wires and the subfloor, and help radiate the heat upwards through the finished floor.