Introducing our new solar rechargeable external auxiliary battery with a capacity of 4,000 mAh. This high-quality battery is made of resistant aluminum material, ensuring durability and longevity. It features a USB output and comes with a micro USB cable for convenient charging. Choose from a wide range of vibrant colors to suit your personal style. Our external auxiliary batteries are designed with your safety and convenience in mind. The capacity mentioned is real, as we only use non-recycled, grade A batteries that have a service life of at least 500 charging cycles. They are also compliant with CE regulations and manufactured in accordance with RoHS standards. To ensure maximum safety, our power bank includes an overcharge protection system, preventing any potential damage caused by excessive charging. Additionally, it has a complete discharge protection system, prolonging the overall lifespan of the battery. A built-in blocking system prevents short circuits, offering peace of mind during usage. The constant charging transfer system adjusts the charging speed to match the capacity of your device, optimizing the charging process. Personalize your power bank today and never run out of battery again!