The Davos Instruments Team has visited the European Solar Test Installation (ESTI) at the Joint Research Centre (JRC) of the European Comission in Ispra, Italy. ESTI is a European reference laboratory for calibration of photovoltaic (PV) devices. ESTI has recently acquired two PMO8 reference radiometers to strengthen its group of references for solar irradiance measurements. Ensuring traceability for solar irradiance is a top priority for ESTI and is key to their activities.