These test strips are an excellent alternative to wet chemical chlorine tests. The unique indicator (TMB) is reactive only to free chlorine; therefore, no interference from monochloramines occurs. Accurate, reliable results are achieved in under one minute, even when measuring cloudy and colored samples. Water Works 2 test strips (3108T40) offer accurate and reliable testing for both free and total chlorine on the same strip. Most are available in packs of 30 individually foil-wrapped strips with a detailed color chart or in a bottle of 50 loose strips with color chart on the label.