Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery

Firstly, I must thank Third Rail (TR) support - they sent new batteries and tried to be helpful.Secondly, here are the pro's to the case (and system).- it is compact- it is intelligent - can charge other devices- it can be popped off and on very quickly.- multiple batteries can be combined or stacked.- the case is a good fit for the iPhone 4S.- the case protected my iPhone 4S very well.Finally, here are the cons,- it is proprietary- the battery hooks snap off over time - TR replaced two batteries.- the battery pops off the case without warning.- two cases failed on me. One had been dropped a few days earlier and the other just died a natural death- customer service seems to have gotten slower.Overall, I would recommend this only if the ability to stack the batteries and use it with other devices are very important for you.AM==== Updated ===As I said before - TR's support is beyond excellent. They back their products and replace defective ones very quickly. I cant praise them enough. However, the problems of battery popping off the case and the hooks snapping off remains due to the design.I did try the Mojo Vogue system but this one is FAR, FAR better than that.AM

Unit does the the job of storing and providing additional power. It is also great that the battery is easily detachable from the outside of the phone without having to tear a bunch of parts off the phone to get at the expansion pack.My only downside: it is TOO easy to detach the battery. It would be great if there was a locking mechanism or lever of some sort. If you put the phone in a pocket or bag where it can get snagged on anything, then the chances are good that it will snag on the battery pack and pull the battery out of the "locked" position (if not off the phone). This is a hassle when taking the phone in/out of any sort of bag (or purse, if you carry one).

The case is beautiful and really thin. The added function of a attachable battery pack is wonderful its just great buy it! u wont regret! alot better den all those other rechargable cases u can get for iphone trust me

This battery and case worked for a short time. First the micro usb input broke loose and I had to remove the case to charge it. Then after a drop the power charging switch broke. I opened this up and was surprised to see not only shoddy materials but a design that was destined to fail quickly. The micro usb port is ONLY fixed by the tiny moterboard, which means the only support is dab of motherboard solildering. That's it, taking a daily or twice a day impace of inserting and removing the charging plug. The power charging switch was just as flimsy. All in all it could be a great product but it's deeply flawed by not being designed for daily use. Buy something with fewer crappy parts. Advice to manufacturer is that fixed parts should have a sturdy and secure mounting and moving parts like switches should be so flimsy, If you doubt this review get a tiny screw driver and peek inside. It is a robust as a onetime proof or the workbench demo not for moving around or daily use.

I bought this case along with an extra battery in 2013. Loved it for a few months. Extra battery stopped holding a charge, I attempted to contact THIRD RAIL in august 2013 with no luck via email and phone. Now the case will not accept a charge, left me without a charger at a business event. I had to shut down and run to get an iphone charger. I have contacted them 3 times via email with a response that says we will contact you in 24 hours and always a recording never a live person.

Shopping was quick and easy overall transaction. Case is great but the battery did not come with it Didn't contact seller because I thought I made mistake assuming the battery came with it.