I've been shopping for a new battery to keep as a spare because mine is getting old. I've looked on Amazon, eBay and several other sites and they all have the C-S2. But the same battery # is listed for several different models. One vendor will show it for the Curve 83xx specifically and then have the same # listed for other phones, and all at different prices. Reviews are mixed at all sites so is it just a gamble on what you receive, maybe old stock is priced cheaper? Is the C-S2 a C-S2 no matter what they say it specifically fits? Who's a reliable source? Thanks for your help.