Features: High quality converter cable for guitar effect pedal. Convert 5.5mm * 2.1/2.5mm to 3.5mm(1/8). Supply power for electro-Harmonix, older DOD, and other guitar pedals that needs a positive tip 3.5mm (1/8) plug. Works well with 9V 5.5mm * 2.1/2.5mm negative center power supply. Length about 20cm.