The Mn6 single molecule magnet shows to date the highest anisotropy barrier for a transition metal cluster. Low lying excited states in the energy level diagram of the molecule have proved to activate efficient relaxation and tunneling paths that have a significant effect in the relaxation dynamics. The full understanding of the relaxation dynamics and of the quantum tunneling processes in these molecules is essential to get a comprehensive picture of their magnetic properties. Here we propose to use the new high-field spectrometer HiFi to investigate the relaxation dynamics of the molecule in presence of an external magnetic field.