People who are worried about their mobile devices running out of juice at inopportune moments now have another portable power supply at their disposal - and it's tiny. The 2.8-ounce (79-gram) Innergie PocketCell is a little larger than a car key, and allows for hours of extra use of Apple and Android devices, MP3 players, and a variety of other mobile gizmos. It was unveiled this week at CES.

The PocketCell incorporates a 2.1 Amp USB power port and a 3,000 mAh rechargeable lithium-ion battery bank. It also comes bundled with the Magic Cable Trio 3-in-1 charging cable, which allows devices with Apple, mini USB or micro USB connections to plug into a standard USB port. It can be charged via USB from a laptop or desktop computer, or using a USB power adapter. Once charged, it can power devices directly, or be used to recharge their batteries.

According to Innergie, a fully-charged PocketCell should be good for about 4.5 hours of iPad use; over 25 hours of talk time on an iPhone, Android or Blackberry smartphone; 100 hours of playback time on an iPod or MP3 player; or over 10 hours of playing time on a game console. A company rep at CES told us that if used to charge the batteries of devices, one fully-fueled PocketCell could manage two full iPhone 4 charges, or half an iPad charge.

The PocketCell is available on the Innergie website, for US$79.99.