After an initial testing period at the Karlsruhe Institute of Technology, the upgraded EU 1 MW, 170 GHz continuous wave (CW) industrial prototype gyrotron (TH1509U) for Electron Cyclotron Resonance Heating and Current Drive (ECRH&CD) in ITER has been transferred to the Swiss Plasma Center (SPC) to be tested in an ITER relevant configuration, to reach the performance level required by Fusion for Energy (F4E) to qualify it for the ITER project, and to increase the pulse length to very long pulses.