Transducers features: Adopting great quality material, which lets you use it for a very long time. Though it is simple in design, it's so practical when you use it. The excellent workmanshlp of our product will bring you a good experience. Easy and convenient to install and use, it is a very useful turbidity sensor. Features Color: Sky-blue Size: 45.50X3.50X3.00cm/17.88X1.38X1.18 inch Material: Plastic Voltage: 3.3-5V Measuring range: 0-1000NTU Made of material for a long time and durable use It has a simple design, but very practical in use, giving you a good using experience Turbidity is the measurement of particulate matter in water. It requires the analog port of the MCU to read the analog value for calculation. It needs turbidity calibration liquid to calibrate. It is not the multimeter that directly measures the voltage. Turbidity sensor is the use of optics, through the liquid solution and scattering rate of transmittance integrated to determine the turbidity case.