The unit of current (often displayed as mA, or milliampere) displayed on your adapter should be equal to or higher than that specified in the manual that accompanies your pedal. Note that this documentation is also available via the relevant product page on the TC Electronic website.  Therefore, if you have an adapter that provides 300 mA and only 100 mA of current is required by the pedal, your Toneprint pedal will work.You must ensure that your adapter is of the correct polarity (center negative pin) and voltage (9V, for example). If the polarity and voltage is incorrect, your pedal will not power and you could potentially harm the unit.