The essentials pH meter is truly the most rugged glass type pH Tester around. It is water & drop resistant. Even if the Tester is accidentally dropped into the water, it will remain afloat. This means you can retrieve the meter immediately without damaging the electronics. It is easy-to-use as you can just dip the Sensor into the test solution - stir & wait. This unit will deliver a stable reading in about 20 S. The meter has a minimum lifespan of about 1 to 3 years depending on the rate of sampling. The energy saving feature shuts off the Tester when it is not in use. The unit also displays a low battery symbol to warn you before it degrades the accuracy of important readings. It has digital calibration at the push of a button & a lit screen for when under dark foliage. Ideal for the following uses: floriculture, agriculture, horticulture, hobby hydroponics, laboratory/scientific, commercial hydroponics, sour mash, beer etc. Just immerse the meter's Sensor into the nutrient solution & take the reading directly. All readings are automatically temperature compensated. The essentials. Ph meter is a rugged glass-type pH Tester. It is water & drop-shock resistant. Both meters are easy-to-use. Just dip the Sensor into test solution, stir & wait. The units will deliver a stable reading in about 20 S. Economical: the meters have a minimum lifespan of about 1 to 3 years depending on rate of sampling. Energy saving: the energy saving feature shuts off the Tester when it is not in use. The unit also displays a low battery symbol to warn you before it degrades the accuracy of important readings.