YSI is a brand of Xylem Analytics active in environmental monitoring, producing the instrumentation and equipment for monitoring and analysing water. YSI products include sensors, software, data collection platforms, biochemistry instruments, colorimeters and photometers, various meters, and platforms. YSI focus on its products in aquaculture monitoring, water quality which are useful in aquaculture areas, environmental health, power/ clean power, civil engineering, food, etc.