Certification : NONEWith Backlight Or Not : YESModel Number : TDS-966Display Type : DIGITALRange: : 0.00~9990ppm (mg/L)Resolution: : 10ppm (mg/L)Accuracy: : 2% F.STemperature Compensation : : 0 ~50Operating Temperature : : 0 ~5010pcs TDS-966 TDS tester Portable Digital TDS meter Measuring Water meter Quality Purity Tester for Aquarium 0-9999ppm 40% offSpecification:Range: 0.00~9990ppm (mg/L)Resolution: 10ppm (mg/L)Accuracy: 2% F.S Battery: 4X1.5V(AG-13) (not included)Temperature Compensation :0 ~50Operating Temperature :0 ~50Auto shut off:10 minDimensions : 147mm27mm18mmweight : 42gOperation:1.Remove the protective cap2.Clean the electrode with distilled water,and suck it with filter paper;3.Turn the meter on byon/off switch4.Immerse the meter electrode in solution up to the immersion level.Under no circumstances immerse above display level.5.Gently stir,wait till the reading is stable,presholdkey, and take the TDS meter out, then use the reading figure x10 to get the TDS value6.After use,switch off and use the distilled water to clean the electrode and replace the protective cap.Calibration:1.Immerse the meter in the distilled water.Activate it about some hours2.Immerse the meter in 6440ppmmg/L) calibration solution(at 25,and stir it gently.3.Allow the reading to stabilize and turn the calibration trimmer with a small screwdriver untile the display shows644.4.Rinse the electrode with distilled water and suck it with tissue paper.5.Immerse the meter in 1390ppmmg/L)(at 25),and stirit gently. Display value must be same as calibration solution(at 25)or approach the value in the area of resolution