I got a Samsung Galaxy S phone about 6 months ago and the phone has been superb, except for the battery life. From leaving home at about 7.00am, by 5.00pm I was getting the battery low warning. This battery has double the capacity of the original battery supplied with the phone. It is also twice as thick, so you get a replacement back, which is moulded for the extra thickness of the battery, but, unlie some similar products, is the normal thickness by the camera lens, which eliminates any problems with vignetting that other products cause. I was a little concerned about how th eextra thickness would affect the feel of the phone, in fact, I prefer it to the original thinner feel. The battery now lasts well over a day and makes the Galaxy S a perfect phone (until the replacment at the end of the contract. One final point on the supplier - the original battery never arrived, but one email and they handled the problem very efficiently with a replacement turning up the next day -excellent customer service!