Foam

Foam, also known as sponge, is either rubber or plastic material with air pockets introduced into it during the production process. This makes it lightweight and flexible. Foam is often classified into two different cell types: open cell and closed cell. Closed cell foams are impermeable to water, air and other substances. Open cell foams are generally softer and more conformable but allow for water, air and other substances to pass through. Foam is commonly used in cushioning, shock absorption, vibration dampening, soundproofing, weatherstripping and sealing applications.