Recently I posted a problem about rebooting when the Droid was jostled or dropped to a tabletop from a short distance. I bought one of the $4 batteries from Amazon. I dropped the Droid from several low levels at several angles and it never rebooted. Clearly the original battery was just slightly smaller dimensionally to allow a brief but significant loss of contact with the Droid. Verizon did send me a "refurb" but I send it back with a note that it was unacceptable to send a phone which at one time had someone else's problems in it as a replacement. I'm so very glad I did.