Lock function: easy to read and record, the instrument will lock the reading 5 minutes automatic shutdown function, the battery will not run out; Measuring range: Specification: Conductivity: 0-9990us/cm TDS:0-5000ppm Degree Celsius: 0.1-80.0 Fahrenheit: 32.0-176.0 Accuracy: 2% Size: 154x30x14mm/6.06x1.18x0.55" Steps for usage: Before use, please unplug the electrode protective cover; Press the power button to put the electrode into the solution to be tested; After the value is stable, press the HOLD key to take out the reading; After the reading is completed, press the power button, wipe the electrode clean, and put the electrode protective cover in; Included: 1 X Water Quality Test Pen Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Dadangjia