pH test paper roll: the pH test strip has full pH range, measures pH values in the range of 0 to 14, pH color chart intervals: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, easy to read | Material: pH paper is made of quality litmus paper, get fast and accurate results in just seconds with the good quality pH test paper | Multiple applications: universal pH paper is good teaching supply for schools, lab, also can be applied to detect fish tank, hydroponics, aquariums, industrial testing, agricultural testing, etc. | Easy to use and operate: remove a small test strip, touch the liquid to be tested, a few seconds later, compare the test results with the standard color on the card board | Scroll design: lightweight and compact reel design for convenient use and carry; Each roll length approx. 16.4 ft/ 5 m, 2 roll, totally 32.8 ft