Below is a list of Open Cell Foam manufacturers from Butler, Wisconsin. Open cell foam is a lightweight, spongy, soft foam in which the cell walls or surfaces of the bubbles are broken and air fills all of the spaces in the material. This makes the foam soft and weak. Open cell foams are incredibly effective as sound barriers, having about twice the sound resistance as closed cell foam. Open cell foam is used for industries such as residential construction which uses this foam as an insulator and sound barrier.