what is the best portable battery for iphone?

Kensington mini battery extender and ChargerThe Kensington mini battery extender and charger extend the iPhone playback time to 30 hours, music playback time to 6 hours, video viewing time to 6
It has large capacity rechargeable Lithium
This also improves the energy efficiency of ion polymer battery packs.
This iPhone battery extender can also be used as a charger for the iPhone, even on the move, it is small enough to keep your iPhone connected.
When you use it on the go, an LED battery meter lights up and tells you how much battery juice you still have.
This is definitely very useful. (Price: $35. 95)
Battery Extender pack and charger for Satechi iCel 4400 mAh iPhone 3G & 3g shere is a simple iPhone battery juice extender that can do the job and provide you
The Satechi iCel battery extender is equipped with a 4400-watt composite interconnect battery and also has a battery life indicator.
The advantage of this charger and battery extender is that you can charge it and your iPhone at the same time.
You can also use it if you have other mp3 players or PDA. (Price: $59. 99)
The TruePower iV Pro iPhone backup battery will not only allow you to use the iPhone almost all day, but will also serve as a power charger for other devices.
It extends the battery power of the iPhone to three times the equivalent of charging, so you can almost ensure that the iPhone continues to power.
What\'s unique about it is that you can use its built-in devices to charge other devicesin USB port.
So if your digital camera or other phone\'s battery runs out, you can use it to provide more extended power to other devices.
The TruePower iV Pro has 3100 mAh power and even comes with a built-in power supplyin flash light. (Price: $99. 95)MiLi Power-
If you would like to provide an extra 8 hours of battery power for your iPhone, MiLi power supply, please pack the case and extend the rechargeable battery by 2000mAh
The packing box and extended rechargeable battery pack can meet this requirement well.
I mean 8 hours of talk time because if you don\'t use the iPhone so much for voice calls, this battery pack and case can give you an extra 30 hours of music playing time.
It also allows you to charge and sync the iPhone to meet the need to remove the iPhone from the power pack.
The battery pack uses smart battery technology to let the battery pack run out of power before switching to the iPhone battery. (Price: $47. 45)
The Mophie Juice Pack Air box and rechargeable battery for the iPhone I definitely saved the best battery for our iPhone battery extender list-Mophie Juice Pack Air box and rechargeable battery.
I have never taken it out of this box since I got the iPhone.
Mophie juice packaging air not only provides solid protection for my iPhone, preventing bumps and scratches, but also effectively provides me with extra battery juice.
It actually has two iPhone batteries because it can double the battery life of your iPhone.
This is enough to give my iPhone a full 24 hours of use before I need to charge.
If you don\'t mind giving your iPhone extra volume, the Mophie Juice Pack Air is the best battery extender you may have.
Did I mention that you would love the gloss and stylish look of it?
It even has three colors: black, white and red. (Price: $79. 95)