The PearlSense T254 UV-LED transmittance monitor from Aquionics measures the percent of UV transmittance, used as an indication of changes in water quality. It utilizes a single lamp and sensor, eliminating drift. It provides a low operating cost, ultra-long lamp life with virtually zero warm-up time and a small installation footprint. It is environmentally friendly, mercury-free, and can be used in a variety of configurations, from hand-held battery operation to in-process installation directly in a pipe, to mounting on a bracket in an open-channel environment. 800/925-0440; www.aquionics.com.