A power bank is a portable device that stores electrical energy to recharge mobile phones, tablets, laptops, and other electronic gadgets on the go. It consists of a rechargeable battery, typically lithium-ion or lithium-polymer, enclosed in a compact, lightweight casing. Power banks come with multiple output ports, allowing users to charge multiple devices simultaneously. They vary in capacity, typically measured in milliampere-hours (mAh), with larger capacities providing more power for extended charging. Many power banks also feature fast charging capabilities, LED indicators to show remaining power, and even wireless charging options for added convenience. Perfect for travelers, outdoor enthusiasts, or anyone in need of backup power, a power bank ensures that your devices stay charged when you're away from a wall outlet.