The DC power jack is 5.5x2.1mm Female To 2.5x0.7mm Male Plug Cable Plug converter adopter.Features of DC Power Jack 5.5x2.1mm Female To 2.5x0.7mm Male Plug Cable Plug Adapter:Small size.Low price.Easy to interface.Applications of DC Power Jack 5.5x2.1mm Female To 2.5x0.7mm Male Plug Cable Plug Adapt..