Boston Power Converter BPC-9V1A; USB to 9V/1A; USB Male 5V; Barrel plug 5.5 x 2.5mm, Center negative; Cable length 50cm; for power supply of effect pedals with USB Power Bank; Stable and clean DC voltage for effect pedals, prevents problems with AC power supplies; Normal analog effect pedals have a working current of 20-30mA. Digital pedals require 40-100mA and multi-effects processors usually work with 300-500mA. Please read the operating instructions of your pedals to avoid overloading.