An electroporation system configured to deliver a pulse of energy to a desired tissue of a mammal to produce a constant current in vivo similar to a preset current input by a user, comprising: (i) a handle assembly comprising: a handle; an electrode array (6.1.3, 6.2.5) having a plurality of electrodes (6.2.4) mounted on a support structure in a spatial arrangement; and a controller in communication with the electrode array (6.1.3, 6.2.5), the controller controlling delivery of the pulse of energy through the electrodes (6.2.4); and a feedback mechanism; and (ii) a packaging system for sterile storage of a plurality of electrode arrays (6.1.3, 6.2.5), characterized in that: the electrode array (6.1.3, 6.2.5) is disposable and removably connected to the handle assembly such that, when connected to the handle assembly, the electrodes (6.2.4) receive the pulse of energy from the handle assembly and deliver the same to the desired tissue; at least one of the plurality of electrodes (6.2.4) is arranged to be neutral during delivery of the pulse of energy and is arranged to measure impedance in the desired tissue and communicate said impedance to the feedback mechanism during delivery of the pulse; and the feedback mechanism is configured to receive the measured impedance and responsively adjust the pulse of energy delivered by the handle assembly to maintain the constant current. (i) a handle assembly comprising: a handle; an electrode array (6.1.3, 6.2.5) having a plurality of electrodes (6.2.4) mounted on a support structure in a spatial arrangement; and a controller in communication with the electrode array (6.1.3, 6.2.5), the controller controlling delivery of the pulse of energy through the electrodes (6.2.4); and a feedback mechanism; and a handle; an electrode array (6.1.3, 6.2.5) having a plurality of electrodes (6.2.4) mounted on a support structure in a spatial arrangement; and a controller in communication with the electrode array (6.1.3, 6.2.5), the controller controlling delivery of the pulse of energy through the electrodes (6.2.4); and a feedback mechanism; and (ii) a packaging system for sterile storage of a plurality of electrode arrays (6.1.3, 6.2.5), characterized in that: the electrode array (6.1.3, 6.2.5) is disposable and removably connected to the handle assembly such that, when connected to the handle assembly, the electrodes (6.2.4) receive the pulse of energy from the handle assembly and deliver the same to the desired tissue; at least one of the plurality of electrodes (6.2.4) is arranged to be neutral during delivery of the pulse of energy and is arranged to measure impedance in the desired tissue and communicate said impedance to the feedback mechanism during delivery of the pulse; and the feedback mechanism is configured to receive the measured impedance and responsively adjust the pulse of energy delivered by the handle assembly to maintain the constant current. the electrode array (6.1.3, 6.2.5) is disposable and removably connected to the handle assembly such that, when connected to the handle assembly, the electrodes (6.2.4) receive the pulse of energy from the handle assembly and deliver the same to the desired tissue; at least one of the plurality of electrodes (6.2.4) is arranged to be neutral during delivery of the pulse of energy and is arranged to measure impedance in the desired tissue and communicate said impedance to the feedback mechanism during delivery of the pulse; and the feedback mechanism is configured to receive the measured impedance and responsively adjust the pulse of energy delivered by the handle assembly to maintain the constant current.