Its a review about this product
I ended up picking this case over the more popular MiLi and Mophie cases after I read some reviews about those cases. This Energizer model was available at my local Best Buy for immediate pickup.
This is a black silicone case with a 1200 mAh battery on the back. The battery is covered in harder black plastic and is not removable. The case is a one piece unit so there are no parts to break or lose.
The silicone material will pick up pocket lint and dust, but it is easy to wipe the case clean with a microfiber cloth.
The rim of the case is raised above the iPhone 4 screen, so the case will provide some additional protection.
One benefit of this case is the improved sound quality of the external speaker. There are two small indentations for the external speaker and the bottom microphone. This feature makes conference calling and speakerphone calls a bit easier to hear.
The battery charging system works very well. When the iPhone and case are fully charged, I can easily get through the workday or a long night out, even while I'm using WiFi.
The Energizer case makes the iPhone about twice as thick. The case won't fit into most docks, but the black silicone material has a matte finish and it hides fingerprints very well.
There's a micro-USB port on the lower right corner for charging. The case comes with a cable, and it's easy to find similar cables at Best Buy. The iPhone will sync and charge through this cable.
There is a small button on the lower left corner that controls the charging mode. It also lights the blue battery status LEDs on the back of the case. The button can be a little stubborn sometimes, but it does work.
This case will handle an adhesive screen shield mounted on the front of the iPhone. I could put an adhesive shield on the back of the iPhone, but I haven't yet.
