When my battery on my W810i died after a year and a half, it was time to find a replacement. I bought my first battery form a company on ebay and was really frustrated with it. It wouldn't hold a charge for more than 24 hours and kept shutting down. I read the reviews here and decided to give this one a try. I have to say I think it is just as good as the original. It also arrived really fast. If you need a replacement battery you really can't beat the value here.