Solar Light’s Model 521 is a 5 channel hand-held ozonometer for measuring total ozone column per standard WMO configuration easily, accurately and dependably. It measures direct solar ultraviolet radiation at 3 discrete wavelengths within the UVB range, as well as total water vapor and aerosol optical thickness (AOT) using the 936 and 1020 nanometer channels. To facilitate field operation, Solar Light offers many options for this model, including a rugged carrying case and Garmin GPS. The unit features accuracy comparable to much larger and more expensive instruments, packaged in a very small, handheld chassis. For more information, please click here!