The Male DC jack converts to a screw terminal if a DC power wall wart needs to be connected to a board that doesn’t have a DC jack. It is a standard 2.1mm female head that can connect to the female DC jack. The terminals are marked with positive and negative terminals to avoid confusion. Many boards like Arduino Uno come with a standard DC jack like this for a power inlet. Compatible with many DC wall power supplies Color: Black & Green Connector Dimensions: 5.5mm (0.2?) jack, 2.1mm (0.08?) center pin diameter Outer Dimensions: 35.3mm (1.39?) length x 13.5mm (0.53?) width x 11.3mm (0.44?) height Weight: 6.3g (0.22oz) Power: 12V~36V Application: CCTV camera, Power, Led and etc Material: Plastic and Copper Working temperature: -20°C ~ 75°C Storage temperature: -30°C ~ 85°C Humidity: 0% ~ 95% RH