The gray silicone closed-cell foam sheet has a medium firmness and meets Aerospace Material Standards AMS 3195 and Underwriters Laboratories UL 50, UL 50E, UL 508, and UL 157 specifications. Also called polysiloxane, silicone is a rubber material that provides flexibility and weather resistance at higher temperatures than other types of rubber. Closed cell foam has internal air pockets that are closed off from each other, making it ideal for sealing out moisture and dust. It has a medium firmness, which requires approximately 6 to 14 psi of pressure to compress.

Industrial foam is made of plastic or rubber and has internal air cells that make it lightweight and ideal for sealing and cushioning.