The Dometic DVF exhaust filter for storage tanks Dometic can go the extra mile, so you don't have to do this. It is always our goal to reduce the use of chemicals, especially in the marine environment. The Dometic DVF exhaust filter ensures this and is designed to absorb the odor from the exhaust port of the air storage tank and keep the surrounding air clean and pleasant. The exhaust filter is made of a filter material that efficiently absorbs odors, so no tank chemicals are required. The kit includes adapters for different exhaust hose sizes. Feature: Old version part numbers 309311004 and 309311001 *sold separately