Stainless steel with piping made of carbon steel, a Bellow or pair of bellows is a device constructed to furnish a strong blast of air whereas a hose is a flexible hollow tube built to carry fluids from one place to another. The shape of a hose is usually cylindrical. As bellows are extensively used to blow on a fire to supply it with air, the simplest type of bellows consists of a flexible bag comprising a pair of rigid boards with handles joined by flexible leather sides enclosing an approximately airtight cavity that can be expanded and contracted by operating the handles. This is then fitted with a valve allowing air to fill the cavity when expanded, and with a tube through which the air is forced out in a stream when the cavity is compressed.
