Ph Test paper pH 1-14 60 mm x 7 mm 100 pieces / bottle Instructions 1. Dip test paper into under testing solution for half a second, then compare the color to the standard color board, the PH value can be obtained. 2. The testing function might lose placing the test paper under sunshine, water or in amphoteric substance. 3. The test papers need to avoid brightness and wetness. warranty period: 3 years