The Medis 24/7 Power Pack is among the first consumer devices that uses a fuel cell to charge portable gadgets. For being the first of its kind, it's a novelty, but the Power Pack is more essential than other digital accessories, should you need to fire up a dying cell phone in an emergency.
We reviewed the 1-watt, 24/7 Power Pack, which works for most smart phones and MP3 players, as well as some portable DVD players and gaming toys including the Nintendo Game Boy. The more powerful, 4-watt Xtreme version of the Power Pack will charge an iPhone.
Design
The Medis 24/7 Power Pack consists of a plain, black box, a bit smaller than 4 inches high by 3 inches wide by 2 inches deep. We'd like it to be small enough to squeeze into a purse, but it's compact enough for a backpack. The pack ships with a power cord and 10 adapter tips for popular digital devices. Output is between 3.6 to 5.45 volts, which shouldn't diminish with time, unlike with consumer batteries.

Getting started was literally a snap. After unpeeling a green label around the device, we squeezed it--hard--snapping its shell's compartments until it collapsed into a smaller size. Next, we shook the box vigorously, hearing liquid slosh around inside, and triggering a chemical reaction to provide power. Within half a minute, the Medis LED lit up and our wilting BlackBerry Pearl started sipping electricity from the Medis Power Pack's included cord and adapter.
While it's working, the LED glows steadily or seems to flash. In either case, the light only indicated one thing: that power was flowing at different rates.

Features
Devices (PDF) the Power Pack can charge include mobile phones from Nokia, Samsung, Sony Erickson, LG, Sanyo, as well as the BlackBerry, Palm Treo, Imate, and iPod Nano. The Olympus AZ-2, Archos 500AV DVD player, Nintendo Game Boy, and other equipment are also supported. (If you don't think such toys would ever need an emergency charge, then you might listen to some Hurricane Katrina survivors who recall the stress relief provided by gaming gadgets.)