AZ Waterproof pH Pen’s raise the bar in ease of use, reliability, function and price point. AZ Waterproof pH Pen’s provide a big IP65 LCD screen with dual pH and temperature display. Wide pH measuring range from 0-14 and a temperature range of -5 degrees to +60 degree Celsius. Waterproof IP65 keypad with simple one touch auto calibration. Also includes a hold button to freeze current readings in low visibility. ATC (auto temperature compensation) ensure accurate readings in all climates. Auto off function maximises battery life.