The Extech EX900 is a complete waterproof (IP57) water quality testing kit that measures Free Chlorine (0.01–10.00 ppm), pH (0.00–14.00), ORP (±999 mV), and Temperature using interchangeable flat-surface electrodes. Ideal for pools, food safety, wastewater, and environmental monitoring, it includes reagent tablets (50 tests), gel-filled pH and ORP electrodes, buffer solutions, sample cups, weighted stand, neck strap, and hard case.