Fast charging on the go: The external battery provides power to smartphones, tablets, Bluetooth speakers, and other mobile devices—whether in the office, on a plane, or at the beach. The power pack delivers a boost of energy while you're out and about. The optimized charging process protects the battery, extending the lifespan of your phone, tablet, and more. Certified cells ensure the highest quality and safe charging: protection against overcharging, overvoltage, overheating, and short circuits. Small and lightweight: The mobile charger fits in any pocket and carry-on luggage. Maximum compatibility for all phones, tablets, and other devices, such as smartwatches, digital cameras, or Bluetooth headphones. A single charge of the powerful battery pack is enough to use the Samsung Galaxy S21+ for an additional 40 hours. The power pack is fully charged in 4 hours via the USB-C port. The integrated LED capacity indicator shows four levels (100%, 75%, 50%, 25%) of remaining power. Input: USB-C. Output: 2x USB-A.