WaterWorks Free Chlorine #480023 CONTAINS 1 BOTTLE OF 50 TEST STRIPS FOR MEASURING FREE CHLORINE LEVELS IN WATER. WaterWorks Free Chlorine Test Strips are designed to be affordable, accurate, and easy to use. They are perfect for determining whether or not you have the correct amount of sanitizer present, and are ideal for testing in food processing environments. The patented technology in each strip prevents bleach out, even at levels above 2000 ppm and resits interference from monochloramines. Simply dip the strip according to the instructions provided, remove excess water, and read your results. It’s that simple. Because our strips have the required reagents built in, no external chemicals are required. Detects 0-25mg/L. This product DOES NOT require an eXact photometer to read results.