The S2-412-SS NDVI downward-looking sensor is a unique two-channel digital sensor for measuring 650 nm (Red) and 810 nm (NIR) with SDI-12 communication protocol. The sensor features a rugged, aluminum housing that is built to withstand harsh conditions, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. The sensor cable includes an IP68 marine-grade stainless-steel cable connector to simplify sensor removal and replacement from permanent installations for maintenance and calibration. Typical applications of NDVI sensors include measuring monitoring plant canopies. NDVI is related to leaf area of the plant canopy and canopy chlorophyll content of leaves and is often used to monitor green up n the spring and senescence in the fall.