1. All models have USB ports, which can charge mobile phones. 2. All models are micro-switching DC power supplies. 3. We have two colors for all models, black and white, you can contact customer service according to the color you want. 4. The output voltage and current can be controlled and adjusted by variable resistors, which provides more convenience and accuracy for the adjustment of voltage and current. 5. The panel also provides high-precision two/three-window digital tube displays of voltage, current, and power, allowing users to intuitively see the current state of use and various parameters of the machine.