Simple, quick, and effective with 0.01 ppm increments, many times better than the most sophisticated test kits or color discs.Easy-to-read digits on the tilted LCD take guess work out of chlorine measurements.Range: Free Chlorine from 0.0 to 2.5 ppm.Accuracy: ±0.03 ppmSupplied with 2 cuvets, caps, 9V battery and instruction manual.