Duplex scanners with automatic document feeder (ADF) are devices that can scan both sides of a document automatically, without requiring the user to manually flip the document over. They are commonly used in offices and businesses for scanning large volumes of documents quickly and efficiently. ADFs can handle multiple pages at once, and some models can scan both sides of a document simultaneously. Duplex scanners with ADFs can save time and effort, and can help to increase productivity in the workplace.