Here is a Mophie JuicePack Plus for sale. This is a good cover and extra battery for iPhone 4/4s. It can charge a phone fully from empty once and keep it charge for about 30 minutes and then the phone is on its own. Very good condition, was only used about 2 months and then put away, It is a matt black in color and only has the face of the phone exposed for use.
Looking for around 70 for this shipped, its about a 7 out of 10
They run around 100 dollars plus tax