DEVZA pH Test Indicator Litmus Paper for Water Soil Testing Soil Test Kit  (Set of 80)

Fast Testing : Simply press the testing strip to the object or liquid you are testing. Half second later, take out the paper and using the color chart included, compare the color change of the paper to find out the acidity level of your testing subject. Can not indicate the Acid or alkali solution when its density was lower than 0.01%.