Holding Tank Vent FilterDometic goes that extra mile so that you don&';t have to and reducing the use of chemicals is always our aim, especially in a marine environment. The Dometic DVF vent filter ensures just that and is designed to absorb odors from a holding tank vent and keep the surrounding air clean and pleasant. The vent filter eliminates the need for any holding tank chemicals since it is manufactured with superbly effective odor-absorbing filter material. Adapters for different vent hose sizes are included in the kit.Features: No chemicals needed Absorbs odors Environmental awareness Brochure (pdf)