Double Roll Hydrion Quat Check Test Paper provides a simple, reliable, and economical means to measure the concentration of Quaternary Sanitizers, specifically Alkyldimethylbenzyl ammonium compounds, Rocall II, and Hyamine 3500. With color matches within the Hi Range of 0-200-400-600-800-1000ppm (parts per million) and the Lo Range of 0-100-200-300-400ppm, the test paper measures concentrations between 0-1000ppm, detecting exhaustion of solutions that should be replaced as well as helping to avoid using excessive amounts of sanitizing agents.