Digital pH Meter by THZY.  Backlit LCD Display, Measures 0-14 pH, .01 pH resolution.  Includes adjustment screwdriver, 2 packets of calibration solution and carrying case.

You can use a pH meter to check the pH of your water, mash, [test Star San effectiveness] and finished beer.

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PH Pen Tester,THZY High Accuracy Pocket Size PH Meter with ATC (Automatic Temperature Compensation) Backlit Light LCD 0-14 pH Measurement Range, 0.01 Resolution Handheld pH Pen Tester