Ah OK. Got it. I saw that but just clicked on the 99.00 one. Looks cool. On B&H there were couple reviews from people who the battery died on, but one was complaining about a recalled model. I think for my use with the 680 I won't need the extension battery. I wonder though, if you have the extension, and they are both connected, if one battery fails, not runs out of charge - but actually fails, could the other battery take over and save the day? That would be an awesome confidence booster out in the boonies somewhere.