For pedals with higher power requirements, the Current Doubler Adapter combines the current of two outputs to power a single pedal. It is most commonly used in combining outputs 5 & 6 on a Pedal Power 2 PLUS to create a single 9V 500mA output. This adapter features two BLACK 2.1mm barrel plugs to a single GREEN 2.1mm jack for use with any standard power cable with a 2.1mm plug. Please note that this adapter will not combine the voltages of the original outputs. Only the current supply will be combined. 4 inch.