Some say this does not work and I don't know why it's not for them.  For me it's great!  I have an LG Optimus.  The is essentially a battery pack that will recharge my phone battery.  I travel for work a lot and now I never worry about my battery running out.  It takes about 2 hours to put a full charge on the phone and I can get at least 2 to 3 charges off of the unit before I need to recharge that.  The unit itself is easy to recharge.  I either plug it into to my computer via USB or I use an iPod style wall charger and plug into that.  This is must for any Android user that can't always be near a power source.