Corrugated metal hoses (also known as jacketed hoses) are ideal for conveying products that need to be heated or cooled during transfer. They are used in asphalt and hot-mix plants and the food, beverage, cosmetic, and pharmaceutical industries. These hoses consist of a flexible inner metal hose enclosed in a flexible metal outer hose (or jacket). Fittings on the ends of these hoses prevent any material that is being conveyed through the inner or outer hose from moving into the other hose. This allows the inner and outer hoses to be used to convey different materials. For example, steam or hot oils can be circulated through the outer hose to keep viscous material in the inner hose warm and fluid.