Taidacent RS485 Modbus 4-20mA 0-5V/10V Agricultural Plant Fertilizer PH Nutrient Phosphorus Kalium Meter Probe Soil NPK Sensor $42.58 - $68.88 Min. order: 2 pieces Taidacent RS485 4-20mA 0-5V/10V Analog Data Logging Sound Level Meter spl DB Data Logger Microphone Decibel Meter Transmitter ...