JTD High Accuracy Pocket Size Handheld pH Meter Pen Tester (Yellow) 0-14pH Measurement Range, Auto Temperature Compensation HOME AND LABORATORY:Test everything from aquariums to home brews with this pocket-sized pH meter FULL MEASUREMENT RANGE: Full pH 0-14 measurements and 0.05 pH range of error AUTOMATIC TEMPERATURE COMPENSATION: ATC accounts for changes in temperature automatically PORTABLE AND CONVENIENT: Handheld, pen-like design includes a carrying case and long battery life EASY TO CALIBRATE: Includes pH 4 and 6.86 buffer packets. CE/FCC/RoHS Approved