Profile: Princo Instruments, Inc. is a manufacturer of level controls in the process control industry. Our level controls are suitable for use on virtually any material such as liquids, slurries, interfaces, granules and bulk solids. We also manufacture precision measurement instruments and controls. Our model LMW-ST/SR-2 microwave level switch consists of a transmitter and a receiver installed face to face. The transmitter emits a continuous low power microwave beam towards the receiver, and an output signal changes state when the beam is obstructed. Our RF Impedance technology is ideal for the widest range of applications, from non-conductive, low dielectrics, to highly conductive materials which leave a thick coating on the sensor probe.