Excellent absorber particularly in the mid-to-high frequency noise ranges. Good structural integrity and requires little mechanical support. Easy to cut and fasten to almost any surface with a water-based adhesive (also available). Convoluted foam features smooth round cone-shaped peaks and valleys which redirect sound waves into the foam where the sound is converted to kinetic energy and absorbed. Convoluted foam gives you 4 times more absorptive surface than flat foams. Standard flat and Aluminized flat foams are sold in rolls, convoluted foam is sold in 4 sheets per box.