PH-901 Pen pH Testr WP Range: 0.00¡ª14.00 pH, Resolution: 0.01 pH, Accuracy: ¡Ü¡À0.03 pH, Temp. C: 5¡ª50¡æ, (ATC) Calibration: Two-point at 6.86pH and 4.01pH (or 7.0pH and 4.01pH) Features: Automatic switch-off function: After 8-10 minutes without pushing buttons, the meter will be switched off automatically. Low battery£ºAs long as there is any display, the accuracy is guaranteed. Battery Life: DC 4x 1.5V Flug: Fixed electrode