You can measure the residual chlorine concentration in tap water. For managing residual chlorine during cooking, as a guide for replacing water purifiers, and for water quality management of ornamental fish. With a magnet, it can be attached to a refrigerator, etc., for storage. The sensor cap with a strap prevents the loss of the cap. Backlight for easy viewing even in the dark. IPX5 splash-proof performance, so it's okay to get wet. Specifications Display Method LCD Display (9-level bar display) Waterproof Performance Splash-proof IPX5 CL Measurement Range 0.00 mg/L ～ 0.80 mg/L CL Minimum Display 0.05mg/L CL Measurement Target Free residual chlorine, tap water only (well water, pools, bathtubs, hot water, hot springs, cold springs, mineral springs, reclaimed water, sewage, etc. cannot be measured) CL Measurement Environment Water temperature: 15 ℃ ～ 25 ℃ pH: 7.1 ～ 7.5 CL Sensor Life 5000 times (life when residual chlorine of low concentration 0.20 mg/L ～ 0.40 mg/L is continued) Power Supply DC1.5V, one AAA alkaline dry cell battery Battery Life 4000 times (1 measurement for 35 seconds) Main Materials ABS, PE, platinum, silver chloride Main Accessories Test battery, one AAA alkaline dry cell battery, cap, instruction manual (with warranty) Amazon selling price is approximately 9000 yen. For restaurants, cafes, bars, and homes. For water quality checks of water purifiers and as a guide for filter replacement timing.