I bought a battery and battery dock charger on eBay for my T-Mobile Samsung Galaxy S2: eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices When it arrived I placed the battery in the dock and plugged it in. While charging the light was red, and when it was charged the light changed to blue. Then I took the battery out of the dock and tried to place it in my T-Mobile Galaxy S2. The battery was a bit narrower and about 1/8 inch longer than the battery that came with the SGS2. I know that the screen on the T-Mobile SGS2 is slightly bigger. I didn't know that apparently the size of the rest of the phone is also different, including the size of the battery. Be forewarned when buying extra batteries for your T-Mobile SGS2. The size of our batteries is different than the other SGS2 phones. If the seller does not say the battery is specifically for the T-Mobile SGS2, it probably won't fit.