Oxidation-Reduction Potential ORP is an abbreviation that represents the oxidation potential of the solution. ORP value is a measure of the ability of the redox solution, the unit is mV. ORP meter test solution redox potential of special equipment. The instrument enclosure waterproof design, waterproof rating of IP55. The electrode can be replaced. With data lock function to facilitate the measurement and recording of data stored; Negative potential (O.R.P) pen The introduction of advanced technology and components, greatly reducing the volume, reduce costs, maintain the original quality, so the use of ORP gained popularity. Suitable for functional energy water purifier and negative potential energy cups and other needs of the determination of the value of having a negative potential. The main technical indicators: Measuring range Range: 0 ~ +/- 1999mg/LmV; Resolution Resolution: 1mV; Accuracy: Accuracy: +/- 5mV; Voltage Battery: 4 x 1.5V (-13 batteries) not included; Operating Temperature Operating Temperature: 0 ~ 50; Correction Calibration: 1 point calibration Procedure: 1.Remove the protective cover. 2.Contact the "ON/OFF" switch,power. 3.Place the electrode in the test solution and gently shake until after the show read the display value is stable. 4.Contact the "HOLD" key,then keep the value of the current measurement.If you need to re-measure,then press the "HOLD" button is automatically released on hold. 5.After use,press the off switch,the electrode with distilled water,put on protective sleeve. Battery installation: If the display is blurry or display, you should change the batteries.When replacing the battery,unscrew the cover,can be replaced,pay attention to the battery polarity CALIBRATION: 1.Immerse the meter in the disilled water.Activate it after a few hours. 2.erse the meter in the calibration solution.And stir it gently. 3.Regulate the trimmer with a screwdriver until LCD screen for 265mV. 4.Rinse the electrode with distilled water,and suck it with filter paper. colour: white + green Material: ABS + electronic components Size: 18.8cm x 3.5cm x 3.5cm Package Contents: 1 x 169E ORP Tester 1 x English manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.