Publisher: uxcell. To use the adapter, simply connect the 5.5x2.1mm female end to your existing power source and plug the 5.5x2.1mm male end into your device. 90 Degree Angle DC 5.5x2.1mm Female to 5.5x2.1mm Male Universal Plug Power Barrel Jack Adapter Converter is a versatile accessory that allows you to conveniently convert your DC power barrel jack.