This is a magical and useful product. Have you ever encountered the following situations? When you travel, you find that your cell phone is running out of power, but even worse, you find yourself forgetting to bring a cell phone charging line. How to do it? In the past, you could only cancel long-planned trips, otherwise you might miss the phone calls or text messages from important people. More importantly, in modern society, you can't walk without a mobile phone. Mobile payment, subway and bus