Specification:  - Measuring Range: 0.00 -14.00 pH;  - Resolution: 0.01 pH;  - Accuracy: ±0.01 pH;  - Batteries: 2*1.5V ( Button cell include);  - Operating Temperature: 0-70℃;  - Dimension: 152mm*28mm.     OPERATION:  1. Remove the protective cap and protective film on the screen.  2. Rinse the electrode with distilled water, and suck it with filter paper.   3. Turn on the meter, immerse the pH meter electrode into the test solution.(can not be over the immersion line)  4. Stir gently and wait about 30s for the reading to stabilize.  5. Turn off the meter after use, clear the electrode with pure water and dry it with filter paper.     Note:  The meter was calibrated before off the factory. Do not need to calibrate the meter when first use.  The glass electrode is fragile, treat it carefully. Don't touch it by hard tools or fingers.  Please do not immerse the meter into the solution over the "warning line", to avoid damage to the circuit board.  If the "cal'(calibration) button is pressed and electrode exposed to air for a long time,calibration is required.     Package included:  1x Digital PH Meter;  3x PH Buffer Powder;  1x User Manual;  1x Carrying case.