If you've ever looked into buying a spare standard battery for your HTC EVO before, then you know that the EVO, Hero, Touch Pro 2, Dash, and some other phones all share the same battery. So pay no mind to that "Verizon Touch Pro 2" designation printed on the back of that 4500mAh battery behemoth you see on the right. It's perfectly suitable for the EVO.
It's packing an extra 1000mAh more than Seidio's 3500mAh battery—the highest capacity officially available for the EVO—and is triple the capacity of the stock battery that ships with the phone.
Whether the stated capacity is actually the true capacity is definitely something to consider with a monster like this, but the more pressing matter you'll need to deal with if you choose to get this battery is how you're going to keep it in your phone. Because unlike extended batteries that are specifically marketed for the EVO, this one doesn't come with a replacement back cover/battery door.
An enterprising EVO owner at the xda-developers forum by the name of daweiteh has fashioned his own cover/door for the 4500mAh battery by modding the Seidio Innocase Extended Rugged case. Full details with pics have been promised but until they're delivered, it's up to you and your imagination to come up with a way to keep this beast contained inside your EVO.[Mugen Power | Mugen Battery]