This crawl sump system helps to remove any collected moisture from the crawl space. The drain has an airtight lid which helps keep water vapors from causing problems. It also has a ball float drain to allow water in. The SaniDry Sedona dehumidifier is the most efficient high-end dehumidifier that you can get. It moves a substantial amount of air through it and can remove more moisture from the air than the dehumidifiers you would find in the big box stores. This keeps the air dry and safe and prevents mold growth.