plug and play, easy to use. Wide voltage power supply of 3.3~5.5V and analog signal output of 0~2.3V make this product compatible with 5V and 3.3V control systems and can be easily connected to existing control systems. The excitation source for measurement uses AC signals, which can effectively prevent probe polarization, extend the life of the probe, and increase the stability of the output signal. The TDS probe is a waterproof probe that can be immersed in water for long-term measurement. The product can be applied to water quality testing in domestic water, hydroponics and other fields. With this sensor, you can easily DIY a TDS detector, easily detect the cleanliness of the water, and check your water quality. Number of probes: 2 Overall length: 83cm Other: Waterproof probe Colour:black Material: PCB Size:4 x 3 x 2cm Package Contents: 1 x Analog TDS sensor module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.