The included electrode has a built-in temperature sensor and amplifier to prevent electrical interference. The large display shows readings in an extended range from -2 to 16 pH and simultaneously shows temperature from -5 to 105 °C or 23 to 221 °F. The MI105 has a stability indicator and hold feature that freezes the display for easy and accurate recording. The large display also has graphic symbols to guide you through all operations. The battery life of the pH meter guarantees over 500 hours of continuous use. When switched ON it performs a self-check and displays the percentage of the remaining battery level to assure proper working condition. Calibration is performed automatically at 1 or 2 points using standard or NIST buffers.