Product operation steps: 1.Remove protective cap. 2.First rinse the electrode with distilled water and suck it with filter paper. 3.Turn the meter on by pressing "ON/OFF" key. 4.Immerse the pH meter electrode in the solution to be tested (should not be over the immersion line). 5.Stir gently and wait around 30 seconds till the reading stabilizes. 6.After finishing, clear the electrode with pure water, turn the meter off by pressing "ON/OFF" key. 7.Always replace the protective cap after use. Easy to Use: Simply immerse the pH meter electrode in the solution to be tested, readings are quickly display on a large lcd display Wide Application: Ideal instrument for any aquarium, the fishing industry, swimming pools, spa, school laboratories, food & beverage, drinking water etc. Fast and Accurate Results: No need to work with those annoying color charts and test strips.Resolution: 0.01 pH, Accuracy: ±0.01 pH Compact Portable Design: Pocket fitting pH meter that's also lightweight and compact. Total concealed fit in your bag or pocket for easy, casual carrying Specifications Display: LCD Digital Accuracy: 0.01 Resolution: 0.01 Operating Temperature: 0~60°C Measuring Range: 0.00~14.00 Probe Type: Precision glass bulb electrode Dimensions:155mm*31mm*18mm Power Supply:2*1.5V LR44 Batteries(Not included )