First rinse the electrode with distilled water and suck it with filter paper. Total concealed fit in your bag or pocket for easy, casual carrying. Users can use it directly. If the data is about 6.86 or the deviation is relatively small, no correction is required; if the value deviates from 6.86 relatively large, press and hold the CAL button for three seconds, let go after the screen flashes, and the automatic correction is in progress.
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