The HI 8424 waterproof portable pH meter can offer nearly the same performance as a top-of-the-line microprocessor bench meter, making it one of the most popular pH meters on the market. By utilizing an advanced, custom microprocessor, HI 8424 is able to perform pH, ORP and temperature measurements with high accuracy and fast response. The mV measurements switch automatically from 0.1 to 1 mV resolution when readings reach 699.9 mV. Temperature effects are automatically or manually compensated for, from 0 to 100C (32 to 212F). The meter has 3 memorized buffer values (pH 4.01, 7.01, 10.01), and automatic buffer recognition to avoid errors during calibration. When powered on, the percentage of remaining battery life is indicated on the display panel. The user can enable or disable the Auto-off feature, the acoustic signal, the back-lit display and choose from either C or F temperature measurements. In addition, HI 8424 indicates buffer values used for the most recent calibration and thanks to the HOLD function, the reading can be frozen on the display to be logged manually.