Radiometers are used in scientific-grade energy balance and surface flux studies. NR01 is a market leading 4-component net radiometer. It offers 4 separate measurements of global and reflected solar and downwelling and upwelling longwave radiation, using 2 sensors facing up and 2 facing down. From these 4 separate components the net radiation is derived. RA01 is a 2-component radiometer, offering two separate measurements of solar and longwave radiation. Both products feature a modular design, low weight, and easy levelling, and low solar offsets in the longwave measurement. The unique capability to heat the pyrgeometer reduces measurement errors caused by dew deposition.