A few years ago, the Therapulse and the Neckpiece were delivered with the new controller. This one has a digital display and no more protruding buttons.
Also the minipulse has the same display since a longer time.
And now also the 4PH and 9PH have the new digital display. Due to the push buttons, the risk of damage is much smaller. The digital display is useful as it shows the remaining session time.
If you still have an old controller or the old display in the minipulse, 9PH or 4PH, you can choose to replace it with the new one.