Designed specifically to accelerate the air flow in non-electric units, the Sun-Mar 12 Volt Fan protects against downdrafts and increases the evaporative performance of non electrical units by 10-15%. The fans are protected against moisture and weather and come pre-installed to fit inline in your vent stack. Sun-Mar In 1971 Hardy Sunberg developed the world"s first self-contained composting toilet that could be put in a bathroom and would evaporate liquids and compost solids. Over the years he developed a rotating drum with three chambers that would become the foundation for today"s toilets. To this day, Sun-Mar remains the world leader in researching and developing composting toilets. From self-contained units, to central units, and even composting toilets that are specially made for RVs and boats, Sun-Mar has over twenty models to choose from, and each is made to fill a specific need. Sun-Mar ensures that each of their toilets take advantage of a using a drum to create compost through aeration and mixing. All Sun-Mar toilets are also certified by the National Sanitation Foundation. * Accelerates air flow in non-electric (NE) units * Protects against downdrafts * Increases evaporative performance of NE units 10-15% * Comes pre-installed to fit inline in your vent stack * Fans are protected against moisture and weather * Perfect for toilets that get a lot of use