This device is designed to accurately monitor the pH and Temperature of your fish tank. It comes with a temperature probe and a pH probe. The temperature probe is permanently fitted to the pH Meter, whereas the pH probe is replaceable. No need to change the whole water quality monitor even after a long period of usage. Simply replacing the pH electrode thus saves your cost. It is equipped with Automatic Temperature Compensation (ATC), so temperature change can' affect on pH level measurement. Backlight: Green backlight pH Calibration: pH 4.01 / pH 7.0 / pH 10.01 three points auto calibration Operating Environment: 0~50℃; 80% RH Storage Environment: -10~50℃; 90% RH Dimension: 90 x 63 x 31mm LCD Size: 26 x 44mm Best to use: You can use this pH meter to monitor the pH and Temperature of any type of water may it be in your aquarium, swimming pool, spa, laboratories, hospitals, hydroponics for laboratory, agricultural, industrial, and also field water analysis procedure. Large LCD display with smart backlight design Compact size with ATC function Replaceable BNC pH Electrode Accurate pH and Temperature reading Power Supply: 4 x AA batteries (Not included batteries) Color: Black Material: ABS Package Contents: 1 set * water quality testing equipment Only the above package content, other products are not included. Note: Light reflection 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.