The 960-0150 pH Controller and 960-0155 ORP Controllers are designed to be simple to install, use and maintain. Simply plug either instrument into a wall outlet, place the submersible electrode assembly in the tank, and plug your metering pumps or alarms into the back of the instrument. Press the appropriate button to adjust the high- and low- set point, and the controller is set to go. The high- and low-set points are adjustable by pressing the appropriate button and turning the adjustment screw until the desired set point appears on the LED digital readout. Calibration is said to be simple, because the electrode is easily accessed and the adjustment screws are located on the front of the instrument. The rugged (ABS) plastic cabinet and clear, plexiglass front panel provide good protection against a corrosive environment.