Fast and Accurate Readings - Just turn it on, dip in liquid and read from display, no need to work with color charts or test strips; Large digital display makes it easy to read. Auto Calibration - No need for any adjustment screwdriver, just complete calibration with auto calibration button and included powder buffer. ATC function- Due to the variability of factors, the temperature of the test objects may have been slightly different, which may cause an inaccurate reading. ATC function can automatically compensate the temperature of test objects, avoid reading inaccuracy. Portable Design - Compact style pen pocket and carrying case makes it easy to slip into your pocket or bag and go with you everywhere. Application - Water analysis in swimming pools, ponds, spas, laboratory testing, food processing, hydroponics, aquaculture and even the home aquarium. Product Description PH meter calibration methods: 1. A packet of correction powder against 6.86 250 ml of water and shake gently. Put pen to detect the pH value of the solution, if the pen is 6.8 accurate display. 2. If the display deviates from 6.8 with a small screwdriver to adjust the calibration potentiometer (opening behind) until the value of the reference buffer solution at room temperature, part of the pH value.< /p> 3. Not corrected when the pen out of water! Easy to use: 1. Remove the protective cover. 2. First wash the electrode with distilled water and dry it with filter paper. 3. Turn on the PH using the ON-OFF switch at the top of the battery compartment. 4. After use, close the pH, rinse the electrode with distilled water and put on a protective cap. Specifications: Measuring range: 0.0-14.0PH Resolution: 0.1 pH Accuracy: 0.1pH Automatic temperature compensation: -55C ~ 0C Power supply: 3 x 1.5V (AG-13 Coin cell type) Ambient: 0~50C RH &lt;95% Volume: 152mm (L) x 29mm (W) x 15mm (D) Weight: 50g Suitable for freshwater and saltwater Note: In the following cases, PH meter needs to be recalibrated: After the calibration has been used or for a long time; Using electrodes frequently Requirements Precision Package Included: 1x Digital PH Meter 1x Screwdriver Calibration Adjuster 1x User Instruction (English) 2x Calibration powder( 1x pH 4.00, 1x pH 6.86)