It is a polyurethane or melamine foam with open cells, which means it has a porous structure. This structure allows sound waves to enter the material instead of being reflected back into the room. As sound waves pass through the foam, they cause the material's fibers to vibrate, converting the sound energy into a tiny amount of heat. This process dissipates the sound energy, reducing reflections, echoes, and reverberation in the environment. The effectiveness of the foam depends directly on its density and thickness. Denser and thicker foams are able to absorb a wider range of frequencies.