This battery comes with: 1 battery pack (slightly smaller than an iPhone); 1 cable to connect it to the iPhone; 1 cable to connect the wall unit to the battery; 1 wall unit. So if you travel that's three extra things you need to carry in addition to the battery. Lose one part and you're out of luck. Why they didn't simply build-in the wall unit to the battery, that would have combined three items into one and would have been simple and elegant.

Pros:
- if I start with a fully charged brick and a fully discharged iPhone and leave them on the table I get close to a fully recharged iPhone in a little while. I haven't timed it but it seems pretty quick.
- because it uses a cord, it charges or powers any device that charges by USB. iPhone (any), Blackberry, GPS...
- you can use the iPhone while it is charging and it still charges (albeit more slowly).
- the brick is pleasantly small and pocketable.

Cons:
- requires a different (mini-usb) wire to charge the brick, so you have to carry an additional wire to recharge the brick after you've had to use it.
- connects to the iphone with a cord. It works to hold the phone to your ear and have the cord dangling to the brick in your pocket, but the cord is a pain. I like the idea of the mophie juice pack, which would still fit in my pocket or on the table or hold up to my ear, with no cord. They don't make that for the iphone 3G yet but I will get one of those too when it is available.
- my particular unit has never showed a full charge from day one, just 4 lights out of five. It works fine, I don't know if it is holding less charge than it should or if the 5th light isn't working, but it suggests less than perfect QA.

I have been making extended business trips, relying on my iPhone for e-mail as well as for entertainment. This battery was just what I needed on travel, and the price was significantly better than at the Apple Store. SuperSaver shipping got it to me an a few days, so I am pleased all the way around.

I've had several "battery packs" for iPods over the years but none have performed as well as this one - and none have had the flexibility of charging methods. I use it with my 80gb Fifth Gen. iPod and it gives me hours and hours of video time and since it charges the ipod battery, you can disconnect it when you don't want to be tethered and you'll have a fully charged iPod.

The fact that it uses a lithium ion battery instead of a NiMh battery is a BIG plus.

Excellent product.

I have an iPhone 3G which needs to be recharged just about every day that it's used. That can be a challenge when I'm traveling, although if I have a laptop it's possible to recharge the iPhone via the laptop's USB port -- as long as the laptop has enough power to spare. The Kensington set is a good backup. It will fully charge a nearly exhausted iPhone battery in an hour or less. You can use the phone while you're charging it (although that means you'll use some of the stored power). The battery has a button that lights up a set of LEDs to show you how fully charged it is. It comes with both a wall plug and a USB cable. It's small enough to carry in a pants pocket. You also have to carry the included cable to connect it to the iPhoe or iPod. You could carry the whole set - battery, wall adapter and two cables -- in a jacket pocket.

The only thing that's missing is a case or bag with a drawstring. One or the other would be very helpful for storing the two cables, the wall adapter and the battery itself.