Rezound Dock question (which way for extra battery?)

[kimintenn]

I purchased the rezound dock (on Amazon) that charges your phone in landscape and also has a spot in the back for the extra battery.
Can anyone confirm which way you are supposed to put the extra battery in? It fits both ways, but I'm not sure which way is correct. One way causes the light on the front to flash and one doesnt. I get top vs bottom LOL, but am confused by front and back.

 

[MrSmith317]

Take a look at the metal fins inside the dock..should be easy to see which way it's supposed to fit.