Keep phones for the whole family at full-charge the next time a power line goes down when you connect to the small but mighty Anker PowerCore 20100. Its impressive output of 4.8 amps can power two mobile devices simultaneously without lag, again and again. No, really. The pocket-sized battery packs more than meets the eye—enough to charge the iPhone 7 almost seven times, the Galaxy S6 five times, or the iPad mini twice when fully charged. Available on Amazon; $39.99.