A USB power bank, also known as a portable charger, is a device that stores energy and can be used to charge mobile devices such as cell phones, tablets, and other USB-compatible devices. It is typically powered by a rechargeable lithium-ion battery and uses a USB port to charge the device. The levo pa71 is one of the most popular models of USB power banks available on the market today. It has 7500 mAh capacity and can charge up to three devices at once. It also features an LED indicator so you know how much power is left in the bank. With its sleek design and powerful performance, it's no wonder why this model has become so popular among users who need reliable portable charging solutions for their mobile devices.