The HI721 Hanna Checker (Handheld Colorimeter) provides a simple, accurate and cost-effective way to measure iron. Naturally present in water in low concentrations, iron may affect the taste of water, as well as stain both laundry and household appliances. Also an indicator of corrosion, iron is monitored in industrial plants and water cooling and heating systems. Designed as a more accurate alternative to chemical test kits, the HI721 provides quick, accurate results in a few easy steps.