We check our instruments according to the procedure and recommendations of our suppliers. We verify all the important functions of the system and write a detailed report of the check-up. For instruments that use a first principal measurement technique (for example particle sizing), the verification of the accuracy is based on certified standard samples. For the other instruments (rheometers, spectrometers and radiometers), calibration standards, also certified, enable to perform calibrations that contribute to maintain the highest standard of quality and traceability. Of course, our own instruments are also regularly calibrated by certified laboratories.