This item is labeled '3-in-1 Precision Hand Water Quality Check Pen' but does not measure PH at all. It's just a TDS meter. Also, the "English" manual has very bad grammar.
π― Honey Refractometer with Automatic Temperature Compensation (ATC) - Tiaoyeer Moisture, Brix, and Baume Refractometer for Honey, 58-90% Brix Scale Range - Honey Moisture Tester
31 Review
Portable digital multimeter with sound continuity and thermocouple (electric tester) LTX DT-838
7 Review
80 Pieces Water Test Litmus Strips Litmus ph Paper Soil Acidity Meter Liquid pH Tester 1-14
10 Review
Accurate And Versatile Digital PH Meters For Food, Brewing, Hydroponics, Pools And More!
7 Review