It's fulfilled by Amazon so it qualifies for Amazon Prime woo!
Amazon.com: Trexcell HTC Thunderbolt 4G 2x1700mah Battery + Charger (Also compatible with MyTouch 4G): Cell Phones & Accessories
There's only a few reviews but at least they say the batteries fit with no problem.
Amazon.com: Trexcell HTC Thunderbolt 4G 2x1700mah Battery + Charger (Also compatible with MyTouch 4G): Cell Phones & Accessories
There's only a few reviews but at least they say the batteries fit with no problem.