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 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, and so on 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, if there is no reaction can stay longer 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