Check the listing for details. 6pcs pH1-14 Test Strips 80 Litmus Indicator Paper Tester Alkaline Acid Testing. Condition: New. Listed at 11.83 USD. Litmus papers are used to determine the pH level of a liquid and determine if a solution is acidic(Red), basic(Blue), or neutral. Widely used for industrial chemical testing, science education, laboratory use, drinking water, swimming pool, spas, aquariums, and classroom analytical chemistry.SpecificationAccuracy: 1 pHTesting Range: 1-14Testing Paper Size: 54mmx9mmOverall Size: 70mmx45mmx5mm (L*W*H)Packing List: 6 x Litmus Test Kit (80/Pack,480pcs)AdvantageThere are 14 color-coded scales that go from 1(being the most acidic) to 14(being the most alkaline). Also can be used to determine the strength of acid and base, as we go from 7 to 1 the acidity of the solution increases.InstructionDipping the pH paper into a solution and observing the change in color of the paper.