The Price: $70 online, but should be available at Best Buy for $60

The Verdict: Convenient. The Fueltank does exactly what it says it does: charge two devices simultaneously on the road. It's made even better because the charging tips are the same ones used in the Chargepod, so you can support just about every mobile gadget you have.

In our test, a completely empty Windows Mobile phone and a completely drained Callpod Dragon charged up to full in about three hours. After this, the Fueltank still had enough juice left to power the phone for another two hours. One quirk though, is that the battery status display only works correctly when the Fueltank isn't plugged in to a power source, and displays somewhere between half to full power when you activate it while it's charging via a wall socket. It works correctly when disengaged and powering other devices.

It's kinda similar to the Powergorilla that we tested last week, but only for smaller portable devices and not laptops. In our view, it's definitely worth $60 as a backup or extended battery, especially if you've got a phone like the T-Mobile G1 that can barely last a day on moderate use. The Fueltank is the same thickness and about 1.5x as wide as the G1, so it's easily slipped into your laptop bag. A good device for anyone who travels regularly and needs supplemental power where there's no outlets to be found. [Callpod]

The Price: $299

The Verdict: It works pretty perfeclty. In our tests, the Powergorilla gave our MacBook Pro an extra 2.5 hours of battery life in everyday blogging usage (Wi-Fi on, lots of app open). That's on top of whatever the internal battery already supplies. The unit doesn't come with a MagSafe adapter, because of Apple's proprietary patent, so you'll have to buy a MagSafe airline adapter and connect via that. It still works, but it's an extra $50 on top of the $299.

Charging phones is an easier premise. As long as your phone can charge from USB, you're set. If not, there are other more proprietary tips and adapters that come with the unit. We couldn't test this ourselves, but Powertraveller also claims that the Powergorilla has many safety features, including voltage limitation, short circuit/voltage/overheat protection. Those are good things to have if you're operating this on an airplane.

Do we recommend this as a gadget? Definitely. Two and a half hours of backup laptop battery is always welcome (more if your laptop draws less power than the beefy 15-inch MacBook Pro), and the ability to emergency-charge your phones, iPods and GPS devices on the go is very handy. However, if you're only going to use this as a backup battery for your notebook, we'd recommend you just invest in a spare battery or two. $299 isn't cheap, but it is worth it if you're a traveler with a lot of different gadgets to charge. [Ecogeekliving ]