pH test paper roll: The pH test strip has a full pH range, measuring pH values from 0 to 14. The pH color chart includes intervals at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14 for easy reading. Material: pH paper is made of quality litmus paper, providing fast and accurate results in just seconds. Multiple applications: Universal pH paper is a useful teaching aid for schools and laboratories, and can also be used to test fish tanks, hydroponics systems, aquariums, industrial solutions, and agricultural samples. Easy to use: Remove a small test strip, dip it into the liquid to be tested, and after a few seconds, compare the color change with the standard color chart on the card. Roll design: Lightweight and compact reel design for convenient use and portability. Each roll is approximately 16.4 ft (5 m) long. Set includes 4 rolls, totaling 32.8 ft.