Fast charging on the go: the external battery powers smartphones, tablets, Bluetooth speakers, and other mobile devices—whether in the office, on a plane, or at the beach. The power pack provides a boost of energy while you're out and about. The optimized charging process protects the battery and extends the lifespan of your phone, tablet, and more. Certified cells ensure the highest quality and safe charging: overcharge, overvoltage, overheating, and short-circuit protection. Small and lightweight: the mobile charger fits in any bag and carry-on. 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 4.5 hours via the Micro-USB port. The integrated LED capacity indicator shows in four levels (100%, 75%, 50%, 25%) how much power is still available. Input: Micro-USB. Output: 1x USB-A.