Irrometer 7 Series Dry Pressure Gauge 0 PSI – 100 PSI 2 in. Dial 1/4 in. MIPT (Bottom)

In use since 1978, the patented WATERMARK sensor is a solid state electrical resistance sensing device that is used to measure soil water tension. As the tension changes with water content the resistance changes as well. That resistance can be measured using the WATERMARK Sensor.