External battery pack Power Devices/Batteries

The Bottom Line: The Callpod Fueltank UNO is a great alternative to form-fitting battery packs. It's well made and provides a solid charging solution for mobile devices.

Specs: Lithium ion, 3 hour(s), 2 in x 4.9 in x 0.8 in

The Bottom Line: The iPWR SuperPack is a compact and affordable juice pack that works well as an emergency extended battery, but it is not something you'll want attached to your iPhone or iPod all the time.

Specs: Lithium polymer

The Bottom Line: The iPWR SuperPack is a compact and affordable juice pack that works well as an emergency extended battery, but it is not something you'll want attached to your iPhone or iPod all the time.

Specs: Lithium polymer

The Bottom Line: If its Micro-USB port doesn't put you off, the Juice Pack Air works well both as a protective case and as a supplemental battery for the iPhone 3G.

Specs: Lithium polymer, 2.5 in x 0.9 in x 4.8 in

The Bottom Line: The Callpod Fueltank is a well-constructed and user-friendly device that works exactly as advertised.

Specs: Lithium ion, 3.4 in x 4.9 in x 0.7 in

The Bottom Line: If you can get over its bulk and price, the Mophie Juice Pack will indeed extend the battery life of your iPhone 3G.

Specs: Lithium polymer, 2.5 in x 0.7 in x 4.8 in

The Bottom Line: The Juice Pack comes at a high price for a glorified battery, but weary, entertainment-starved travelers will appreciate the extra time it offers.

Specs: 24 hour(s), Lithium polymer

The Bottom Line: The Kensington Mini Battery Extender is a handy add-on for an iPod or iPhone that's low on battery life.

Specs: Lithium polymer

The Bottom Line: The iPhoneck Backup Battery is easy to use and it works as promised. We just wish it had a sturdier construction.

Specs: Lithium polymer, 1.6 hour(s)

The Bottom Line: The iPhoneck Backup Battery is easy to use and it works as promised. We just wish it had a sturdier construction.

Specs: Lithium ion, 1 hour(s)