The NR01, manufactured by Hukseflux and cabled for use with Campbell Scientific data loggers, is a research-grade net radiometer that measures the energy balance between incoming short-wave and long-wave infrared radiation versus surface-reflected short-wave and outgoing long-wave infrared radiation. Our data loggers measure the NR01's output and control its internal heater. This net radiometer offers a professional solution for scientific-grade energy balance studies. Note: NR01 radiometers with a serial number less than 2313 used the pn 21271 fitting. NR01 radiometers with a serial number greater than 2312 do not need the pn 21271 fitting.