Features:Fast easy to read results with large duel level digital LCD readout.Extreme accuracy to ±0.02 pH / +/-0.5°C (+/1°C outside) / +/-1°F (+/-2°F outside).Extended range (-2.00 pH to 20.00 pH).Lightweight and portable, IP67 rated.Easy measurement: just place the probe in the sample, gently stir and wait for the reading to stabilize.Simple push button, automatic up to 3 point calibration for increased accuracy.Gel-filled, double junction, amplfied, rugged field design, with lab grade performance. MA906BR/1 pH electrode is low maintenance with high accurate results and has a screw on cap to ensure proper storage.Built in temperature sensor. Battery life aprox. 200 hour (battery included).Auto shut off feature to preserve battery energy. Alphanumeric LCD display messages for friendly, intuitive information, warnings and error messages.Internal clock date to keep track of different time-dependent functions (calibration, timestamp,calibration time out).3 feet probe cables for extra flexibility when testing.The Milwaukee MW105 MAX Waterproof 3-in-1 pH/OPR/Temp. meter has won fans around the world with its reliable, fast and simple operation as well as its toughness and IP67 Waterproof rating. Accurate to ± 0.02 pH with automatic or manual temperature compensation, and built in GLP key. Ideal for use by brewers, wine makers, growers, labs, food processing, water treatment and many other applications with challenging pH measurement needs.The Milwaukee MW105 MAX Waterproof 3-in-1 pH/ORP/Temp Meter is preferred by people testing samples in viscus applications that cause other pH testers and meters to fail. From brewers and wine makers to hydroponic growers and farmers the MW105 is your meter for fast, accurate readings.People choose the MW105 MAX Waterproof 3-in-1 pH/ORP/Temp Meter to improve the accuracy of their testing program. With up to 3 point calibration and 7 standard buffer choices, the meter can be quickly calibrated to a higher accuracy compared with one or two point calibration. The MW105 meter is accurate to ± 0.02 pH. 5x more accurate than some alternative meters.The meter comes with an amplified, combination pH probe with a built in temperature sensor allowing the meter to automatically adjust the pH reading for the effect of temperature.The meter can also be used as a very accurate thermometer with accuracy +/-0.5°C (+/1°C outside) / +/-1°F (+/-2°F outside)The glass bulb loses sensitivity with use and will eventually fail. This is true of all pH probes.The reference junction is a small hole that allows the meter to compare the sample to a reference. The reading is generated based on the electrical difference between the sample and reference. If the junction hole gets clogged, the pH electrode will no longer function. The pH probe needs to be kept hydrated. Long periods of dry storage will damage the sensitivity of the probe. Allowing the probe to dry out may also result in the junction hole getting clogged.Storing in pH probe storage solution MA9015 or pH calibration buffers will help address both these issues. Do not store in tap water and DI water. This will damage the sensitivity of the probe.The best way to store the probe is with the probe's cap filled with storage solution or calibration buffer and the cap tightened to prevent leakage. It is also recommended that to store the electrode upright to further reduce the potential for leakage.Residue from the sample can impact the sensitivity of the sensing bulb and clog the junction. This is especially true if the sample has a lot of material.recommend regularly soaking your electrode in cleaning solution MA9016.The pH sensing bulbs become less sensitive over time so make sure that are calibrating regularly to keep your PRO Plus pH meter accurate. Also, calibrate after cleaning or a long period of storage.