IKN AC 100V-240V Adapter Cord DC 9V 1A Wall Charger Power Supply Center-Negative US Plug Adapter for Effect Pedal 100V-240V AC to DC Charge Adapter. Output: DC 9V 1A. Input:100V-240V 50-60Hz. Plug: the outside diameter 5.5 mm, the inside diameter 2.1mm. Center-negative.