Apera Instruments, AI482, TN420 Portable White Light Turbidity Meter, EPA 180.1 CompliantApera TN420 is built with a tungsten filament lamp as the light source and uses the 90° scattering method, which is compliant with the U.S EPA 180.1 method for the determination of turbidity in drinking, ground, surface, and saline waters, domestic and industrial wastes. The instrument is designed for water quality professionals, offering long-term reliability in high-accuracy turbidity measurement with an intuitive operating system and simple calibration.AI482 Includes Only:AMCO calibration solutions (0, 20, 100, 400, 800 NTU)6 pieces of sample vialsSilicone oilMicrofiber wipeUser manual.Features:Premium-quality tungsten filament lamp as the light source, especially ideal for testing low-range water (<10 NTU). The lamp is replaceable.The kit comes with AMCO high-molecular polymer turbidity standard solutions (0, 20, 100, 400, 800 NTU), which are EPA approved primary standards that are safe, non-toxic and disposable, and have a guaranteed one-year shelf life. It is NIST traceable to particle size/distribution and optical density, and its inherent stability means it does not settle from suspension. Store the standards at room temperature. They must not be frozen.The average measurement mode automatically takes multiple consecutive readings and calculates their average value.Large TFT color screen with simple operation guide, supporting English, Spanish, and Chinese.3.7V rechargeable lithium battery can supply power for up to 20 hours of continuous measurement. The battery life is 5 times longer compared with other products in the market.Everything comes in a rugged carrying case, including AMCO calibration solutions (0, 20, 100, 400, 800 NTU), 6 pieces of sample vials, silicone oil, a microfiber wipe, and a user manual. ... Show More Show Less