Designed for highly accurate electronically controlled variable flow control of inert fluids and gases. Using analog or digital signal inputs to produce a linear variable flow output, this combination of a stepper motor, valve body with controller circuit has more than 1,500 positions through its valve stroke which can be dialed down to the step, creating reliable and repeatable flow rates from 0 to 30 GPM (water) @ 150 PSI. The valve features a built-in electronic control that accommodates either open or closed-loop control by use of electronic signal input of either 4 to 20 mA, 0 to 10 Volt DC. Valve standard operating voltages are 12 or 24 VDC. The Stepper 12 has a separating diaphragm that maintains dry mechanical movement and is designed for long life and high flow. The diaphragm is designed with a specialized convolution and elliptical flow tip producing a linear flow versus valve stroke position.