pH Pen pH Range 0.00 to 14.00 Waterproof IP67 Automatic Temperature Compensation Yes Operating Temp Range (F) 50 Degrees to 104 Degrees Operating Temp Range (C) 10 Degrees to 40 Degrees Display Dual Line LCD Auto Power Off Yes Calibration 3 pt. Power Source (4) 1.5V Micro Alkaline Batteries Manufacturers Warranty Length 1 yr. Range 0.00 to 14.00 Number of Tests 0