How deep can you stimulate using the PowerMAG?

This really comes down to the properties of the coil utilized. The two main style of stim coils used within the TMS field are figure 8 and round, with figure 8 often being preferred for focal targeting. Typically with the figure 8 coil you would get greatest stimulation at a depth of roughly 2- 2.5cm, with a round style you may achieve a bit more penetration ~2.5-3cm.