Features:100% brand new and high qualityApH meter is an electronic device used for measuring the pH which is either the concentration of Hydrogen ions in an aqueous solution or the activity of the Hydrogen ions in an aqueous solution. The pH will indicate if the solution is acidic or basic, but is not a measure of acidity or alkalinity. pH meters work in liquids though special probes are sometimes used to measure the pH of semi-solid substances.A pH meter consists of a special measuring probe (a glass electrode) connected to the body which measures and displays the pH reading.Specification: Instrument Level: Grade 0.01 PH Measuring range: PH 0.00~14.00pH PH basic measurement error: ± 0.05pH Instrument Repeatability: ±0.03pH Solution temperature compensation range: 0 ~ 60°C instrument repeatability 0.03pHmV measuring range: -1400mV~+1400mV temperature range: -10 ~ 60 ; 0.1°C Battery: 9V Battery (not included) Display: Large LCD segment type display with back light Working temperature: 0 ~ 35°C Working humidity: 0-80% R H ( Non Gel) Weight Approx.650g/22.9oz Product Size17.2*6.2*3cm/6.8*2.4*1.2inExplanation of appearance: 1. ON/OFF 2. mode button 3. MAX/MIN HOLD button 4. C/F selection button 5. CAL/back light button 6. LCD Display 7. electrode plug 8. Electrode assembly 9. Electrode liquid storage bottle LCD Display: 1. Battery indication 2. HOLD function 3. MIN Measurement 4. MAX Measurement 5. PH measured value6. READ fuction 7. Temperature Measured vale Normal Condition of use: (1) the environment temperature (0 ~ 35) ; (2) the relative humidity is not more than 80%; (3) measured solution temperature: (5 ~ 60 ); (4) power supply: 9V DC battery X 1pc (006P); (5) no significant vibration; (6) in addition to the earth's magnetic field without external magnetic field outside interference. User's Guide:Openthe battery door that located at the back of the instrument, insert a new 9V battery into this compartment with correct polarity. If you have replaced with a new PH composite electrode, please do the calibration before use this unit to measure.If measuring interval time is short, one month calibration once is enough.This instruction use three point calibration method for a librate this unit, please following the step one by oneThe unit and calibration solution must be calibrated at ambient environment temperature 25 C +/-2 C. (1) Press "MODE" key go to three different calibration mode (CAL 1), (CAL 2) and (CAL 3). (2) accordingto the "mode" button instrument into the correction state, respectivelyinto "C4.0" "C6.86" "C9.18" three states cycle scintillation indicating symbol. (3) Correction steps are as follows: A: PH4.00buffer solution calibration: Press"MODE" key go to (CAL 1) icon shown and flashing, rinse the PH electrode with distilled water, immerse the electrode in the PH4.00 buffer solution, wait for the electrode become stable, you should find the value of mV don't change and state at same value, this time press (CAL ) key more than 3 seconds. until (4.00)flashing stop and disappeared, so the PH4.00 calibration completed. B: PH6.86buffer solution calibration: Press "MODE" key two times go to (CAL 2) icon shown and flashing, rinse the PH electrode with distilled water, immerse the electrode in the PH6.86 buffer solution, wait for the electrode become stable, you should find the value of mV don't change and state at same value, this time press(CAL )key more than 3 seconds.until (6.86) flashing stop and disappeared, so the PH6.86 calibration completed C: PH9.18 buffer solutioncalibration: Press "MODE" key three times go to (CAL 3) icon shown and flashing, rinse the PH electrode with distilled water, immerse the electrode in the PH9.18 buffer solution, wait for the electrode become stable, you should find the value of mV don't change and state at same value, this time press(CAL) key more than 3 seconds.until (9.18) flashing stop and disappeared, so the PH9.18 calibration completed. (4) normal measurement mode: The factory default mode is normal measuring mode if you press ) the power on/off ) button to turn it on. At this normal measure mode, the unit can measure the PH and environment temperature at the same time, just immerse the electrode into the solution that you want to measure the PH value mV measure mode:Press"MODE" key four times go to mV measure mode,which enable you to measure the ion -selective, ORP(oxidation-reduction potential) and other precise mV measurements. At that mode LCD display screen show mV and ambient temperature at the same time. (5) Ifthe battery power indicator icon become empty,please replace a new 9V battery immediately, If the instrument will not be use in a long period,please take out the battery from the battery compartment to prevent anyleakage