Need a little portable power? The RAVPower Dual USB Charging Bank refills your battery at a speed of up to 3 amps and can fill a Galaxy S5 over three times on just one charge. There are plenty of power supply options floating around online but not many are #1 best-sellers with 5 star reviews. With a built-in flashlight and LED’s rounding out the feature set, this is a great buy at just $29.99 (Prime).
Also worth checking out: