16 in 1: Test total alkalinity, PH, hardness, lead, copper, iron, mercury, chromium/hexavalent chromium, bromine, nitrate, nitrite, residual chlorine, fluoride, sulfite.Health: The test paper is used for water quality testing of drinking water, household taps, well water, fresh water pools, etc. For health, please use professional drinking water test paper to test the water quality standard.Easy to use: submerge the drinking water test paper in water for 5s, let it rest in air for about 30s, then match the color of the test paper with the color on the back of the bottle to get the reading. Drinking water test strips are easy to use even for beginners.Economical: Water quality should be tested weekly.Easy to carry, very convenient to carry to any place