I bought this battery as a replacement for my original Samsung Galaxy S2 battery, which has unfortunately made limp after only 4 months. The delivery came too promptly, just did not fit anything. By some processing error on the battery while it fit into the phone, the back but could no longer be close. Then I turned to the seller who sent me within one day with a new battery. This now fits wonderfully in my Galaxy S2 and the duration is just great. Despite intensive use (telephone, internet, WiFi, Bluetooth, ...) he held now almost 2 days. Am satisfied!
