Ejectors and eductors are used to lift, pump, mix and agitate liquids, granular solids and slurries. They are sometimes called aspirators, Venturi pumps, or jet pump ejectors. Because eductors are non-mechanical, they do not include moving parts or require lubrication. Because they do not require electricity, eductors can be used in hazardous environments. Eductors use the kinetic energy from a stream of compressed gas or liquid. The movement of this stream through a tapered tube and Venturi nozzle increases the pressure of the flow. The subsequent discharge of the stream then creates an area of low pressure that draws in the contents of the suction chamber. Mixing occurs in the diffuser and the motive fluid is released through an exhaust port. Often, eductors are made of polytetrafluoroethylene (PTFE), a fluorinated thermoplastic with outstanding chemical resistance and excellent lubricity. Eductor nozzles are usually made of stainless steel.