Below is a list of Filter Foam manufacturers from Baltimore, Maryland. Filter foam is open cell foam that allows air and water to pass through it while trapping and catching small particles like dust and dirt. They are used to maintain cleanliness and lengthen the lifespan of many different products, machines and systems in industrial and commercial settings. Around the house, they are most likely seen in aquariums to keep the water clean, vacuum cleaners to gather dirt and clothes dryers to catch lint.