The D380 Iontophoretic Dye Marker provides an isolated, bipolar and constant current output intended for cell labelling or cell marking of individual neurons with charged dyes, such as Lucifer Yellow, via iontophoresis. Holding currents of up to ±6nA and injection currents up to ±12nA are possible and precisely set by single-turn panel mounted dials. A compliance voltage in excess of ±6V allows the full injection current into electrodes with impedances up to 500Mohms. An LCD screen continuously displays the polarity and magnitude of the requested Injection and Holding currents as well as the electrode resistance and the voltage applied. The unit is powered from a single, standard, 9 Volt battery.