pH paper rolls: pH paper has a full pH range, measures pH from 0 to 14, pH colormap intervals: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, easy to read Material: The pH test paper is made of high quality litmus paper, use high quality pH test paper to get fast and accurate results in seconds Multiple Applications: Universal pH test strips are good teaching supplies for schools, laboratories, and can also be used to test fish tanks, hydroponics, aquariums, industrial testing, agricultural testing, etc. Easy to use and operate: take out the small test strip, touch the liquid to be tested, after a few seconds, compare the test result with the standard color on the card board, if there is no response, it can stay longer Reel Design: Lightweight and compact reel design for easy use and portability; each roll is about 16.4ft/5m in length, 2 rolls for a total of 32.8ft