ok, I guess I see the case now but the "extra" battery looks hinged onto the back side of the phony. So does the case have additional battery capacity built in? Is the hinged battery in addition to a case battery or is the hinged battery needed to get any additional capacity.
Sorry but those pics are really difficult especially with a phone. It's like they didn't expect phones to be viewing the page?
BTW, the powerskin extra battery looks like a similar concept but doesn't require the bulk of a another case.
http://www.power-skin.com/popn/htc-battery-charger.php