A power bank is usually a rechargeable battery that can transfer power to other electronic devices. Power banks are like wall outlets that you usually takes with you. Simply plug in your phone or laptop via a standard USB-A or USB-C cable, and boom, you might have instantaneous portable power. https://modernsmarthealth.com/product/smart-home/alternative-energy/10000mah-solar-charger-2-usb-ports-solar-power-bank-bateria-externa-portable-charger-for-smartphone-for-iphone/