Are you in favor of a removable battery type for your iphone 4? Then you and Third Rail System are on the same page. They have come up with a smart light-weight protective case with a soft-touch feel and a 1.4 ounce 1250 mAh lithium-ion battery that slides on the back, offering you with extra power if your phone runs out of charge on a busy day. With a micro USB port, this case also acts as an independent, universal charger for most mobile devices. This is a removable battery type and when you do not need that extra power you can always keep it aside and when you need it just slide it back on. By the push of a button, you can check your phone’s power level. It also allows you to load several smart batteries together and create a power hub that can be charged by a single adapter.
This product is exclusively “Made for iphone 4” and it has got Apple’s approval. It comes with a case and a single slide-on battery. The case comes with a $40 price tag and the battery for a neat $60. This will be a good substitute for those heavy power cases and bulky external chargers.