Made for iPhones and iPads—and nothing else!—the Mophie Juice Pack Boost is a handy little extra battery which can give your iDevice just a bit more charge. While it's slim and well-designed, we find it lacking in power and flexibility compared to other recharging options.

The Boost is a light (2.5 oz), petite (2.2 by 3.9 by .37" HWD) little rectangle that comes in black and red soft-touch plastic. It feels like a premium device, and at $49.95, it costs more than comparable 2000mAh batteries. It charges quickly using an included MicroUSB cable, but it doesn't come with a power adapter; you have to plug it into your PC's USB port, or use your iPod/iPhone's adapter to charge it. Pressing a battery-check button on the right hand side lights up four green LEDs to show how charged the device is.

To power up your phone, pod, or pad, there's a swiveling 30-pin Apple docking connector. That's it. This won't charge non-Apple devices.

The battery should give you more than a full charge for an iPod touch or iPhone. I plugged it into an iPad 1 (4.5 stars) running our standard test, and got an extra hour and 48 minutes of video playback time, a little below what I expected from the 2000mAh capacity.

The Boost falls short when considered against its competition, though. At the single-charge-for-a-phone level, we'd suggest looking into charging cases instead. Mophie's own Juice Pack Plus ($99.95) has the same capacity, but builds it into a case, so you're never without your spare battery.