Flow wrapping is a packaging process where a product moves horizontally through a machine and is wrapped in clear or printed film and sealed to form a pillow-shaped pack. Flow wrapping preserves and protects a product, improving its shelf life. The process is also known as horizontal bagging, pillow-pouch wrapping, fin-seal wrapping and crimp-seal wrapping. As a packaging process, it is most suited to packaging a large number of identical items that can be moved along a conveyor belt (small, loose, granular products aren't suitable for flow wrapping - vertical form fill seal works best for this kind of product). Flow wrappers range from stand alone machines for low speed, hand fed applications to high speed, fully automated units integrated into sophisticated food processing and packaging lines.