1. Highly Sensitive Probe: Get the EC/TDS/PH/Temperature readings quickly. 2. Stable Reading: Anti-jamming chip gets stable readings. 3. Reliable Reading: The measurement reading does not change when the liquid temperature increases or decreases. 4. 0ne-tap lock Reading: 1-tap keeps the pH meter measuring, easy to record the reading. 5. Other Features: Auto Power Off; Display with Green Backlight; IP67 Water Resistant; Convertible Temperature Fahrenheit ℉ and Celsius ℃. How do I calibrate the pH meter? To calibrate your pH Meter, please follow the steps below. 1. Before calibration, add the pH4.00/pH6.86/pH9.18 buffer powder to the beaker with 250ml of distilled water, then stir until the powder is completely dissolved. 2. Place the electrode into the pH4.00/pH6.86/pH9.18 standard solution and wait for the reading to stabilize (usually 5~10 seconds); 3. Press and hold the MODE/CAL button and release after 6 seconds; Wait until the pH4.00/PH6.86/PH9.18 reading stops flashing. Size: about 7.2 x 1.47 inches Weight: about 164 grams / 5.8 ounces Range: pH value: 0.00 to 14.00pH EC: 1 to 19999us/cm TDS: 1 to 19999ppm Temperature: 0 to 60.0°C / 32.0 to 140.0°F Colour:Red Material:plastic Package Contents: 1 x ph meter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.