Water Quality Digital Tester High Accuracy [ Storm Buy ] pH Meter / pH Tester with ATC + TDS Tester Aquarium Pool Hydroponic Water Monitor 0-9999 PPM PH Meter features ATC (Automatic Temperature Compensation), Long battery life PH Meter is easy to calibrate with the pH 4 & 6.86 buffer packets. No calibration needed for new purchased unit PH Meter with Handheld pen-type design for portability and convenience with carrying case; CE/FCC/ROHS Approved TDS Meter with Lightweight, handheld design; factory calibrated;CE/FCC/ROHS Approved TDS Meter with a Measurement range of 0-9990ppm and 2% highly accurate and quick readings