Jackery Giant is an external rechargeable battery for backing up portable devices when you run into a power desert. The Giant has two USB output ports (1 amp and 2.1 amp) for powering two devices at once, plus a charge-status indicator. The maker claims the battery will hold its charge for six months.
The good: I normally wouldn't care what a battery looks like, but this one is space-age gorgeous, and its slick aluminum body, measuring 4.3 by 3.1 by .08 inches, slides easily into a carry-on pocket. The real plus is that it packs a punch. This backup battery can power up my iPad to at least 60 percent of capacity - and sometimes a bit more. For phones or MP3s, you would have a seemingly bottomless pit of power.
The bad: The Giant itself takes a while to charge fully; it seemed to average about 12 hours for me with a wall charger, not included.