I bought this battery cover in order to use the GPS function for a long period in cycling can. As also works very well, because the performance of the battery is very good. Visually, the shell is okay, but smells a little 'China'.
Very disadvantageous, however, that the shell deteriorates receiving the iPhone. This gave me repeated during and after the bike ride no more power.
A shame because the charging function was perfect. Now I am afraid to look any further ...