Sony NP-FM500H on sale at Sears (USA)

Counterfeit. that is why they are so cheap.  I had cause to check a battery I bought via Amazon in a pack like that and returned it.  Your purchase might work OK, it might give trouble, (eg stop the battery door from opening - see a post today), could invalidate your warranty etc.  Suggest to Sears that they contact Sony and provide them with a battery in its pack to confirm.   The email address is stopfakes@am.sony.com .  There are a few threads on the subject eg see

http://forums.dpreview.com/forums/post/39703867

My list of faults was:

The labels were quite unlike those on the recent, genuine battery (but had some resemblance, though not identical) to an old battery I had with my A700).
The last line of the top part of the battery label had "tohightemperatures" without any spaces.
The angle of a slot on the side was slightly different (not easy to see in pictures).
The Sony label stuck on the front, top left of the package was green, not brownish.
The text lower right of the package reading Cybershot  HANDYCAM was clearly mid blue, not very dark blue/black.
The stamp marks that seal the closing of the package were oblong whilst the genuine had an oval/round stamp mark over the oblong.
The plastic of the package was extremely brittle.

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Sandy