Editors' note: We updated this review on April 21, 2009, to correct an error. The Juice Pack uses a Micro-USB cable instead of a proprietary cable.
Considering the iPhone 3G's short battery life, an extended battery should be the first accessory you buy. The $80 Juice Pack Air is the newest of this sort of accessory, and it is the thinner, lighter version of Mophie's $100 Juice Pack. The Juice Packs are cases for the iPhone 3G that also act as extra battery packs, thanks to their included lithium polymer batteries.
The Juice Pack Air looks identical to the original Juice Pack, with one addition: the top portion of the phone is now covered, giving the iPhone complete protection. The "air" in the name refers to Mophie's contention that the new case is thinner; however, with dimensions of 4.9 inches tall by 2.59 inches wide by 0.75 inch thick, the new case is not much smaller than the original. Also, it adds about 20 percent more weight to the phone, which is slightly lighter than the original Juice Pack. Aesthetically, the new Juice Pack is a better-looking case than the original version.
The "Air" in the name also indicates that you won't get as many hours of battery life from this case as you would from the slightly bulkier original.