2 rolls, lightweight and compact spool design for easy use and portability. The pH test paper is made from high quality litmus paper which provides reliable results in seconds in the pH range 0-14. Indicator strips come on a roll, just pull them to your desired size. Take a small test strip, touch it with the liquid to be tested and after a few seconds compare the test result with the standard color of the cardboard. pH tests are commonly used to check acids and bases . Ideal for testing saliva, drinking water, aquariums, hydroponics, food, soil, detergents, soaps and more. The universal pH test paper is a good educational resource for schools and laboratories, and can also be used for testing aquariums, hydroponics, fish tanks, industrial testing