Hey guys I had recently bought an extended battery for my Evo 4g. It was a great idea. I bought the really cheap 15$ ones that are all other ebay. They work nice they do give you extended battery but, In my opinion it is not worth it to add that much chunk for how much extra battery life you are getting. I would go with the seidio extended battery they are expensive but if you want to spend the money then you will be better off going with that one. Also the Chinese battery get better the first week you use it and then starts to get worse everyday you use it so it was only good for about a week and then it started declining in how much time I had to play games text call and use my phone. After about a month the battery started being as good as the stock battery so i just took out my extended battery and used the stock one. The bad thing about the stock one is that when you set your phone down then you scratch the camera. I was looking at my camera and it has a lot of scratches on it. So I decided to buy a case. If you are looking for a battery that is cheap and will last you a couple of months then this is the battery for you. I have did a review of the battery in a youtube video at the bottom of this post so you can see exactly how much chuck this extended battery gives to the phone. Maybe I got a defective battery but you can test it out for yourselfs. In the video I also go into a little bit on how to improve battery life so check that out at the bottom of this post.