5,100 mAh Portable Battery Pack
Samsung's official 5,100 mAh portable charger will recharge the Galaxy S8 battery 1 1/2 times. It's a small square block that's easy to put in a purse or pocket. It also comes with a new USB type-C port for charging the S8.
These were $59 last I saw, which is a little more than most of the competition. Better options with a larger battery are available on Amazon from Anker or Tronsmart.
Buy it Now for $59.99