These products use cellular materials as polyurethane polyester, low density microperforated polyethylene and polyester mats for the damping of sound waves.
Open cell foam sandwiches and mass barriers (rubbers with specific high weight or thermoplastic polymers) are used to limit sound transmission from the source to the external environment. According to the mass-spring-mass principle.
Sound absorbing and heat resistant materials are self-supporting or flexible to be glued through mastic or double-sided adhesive tape. They could be equipped with a protective film in polyurethane or aluminium or nonwoven fabric.