Fisher AOS 220 is an electro-pneumatic positioner designed for small valve actuators. It is designed to help keep the valve in the right position and is capable of providing precise flow control. The AOS 220 is easy to use and is suitable for a wide range of applications. It can be used to control the position of a valve such as in a boiler, oil pipeline, or any other liquid-handling system. The AOS 220 also provides control over the flow rate and pressure of the process stream. With its high-precision and reliable design, the AOS 220 is ideal for many industries including chemical, petrochemical, oil & gas, energy and water/wastewater.