Great price for this replacement battery. After reading other reviews I selected the vendor for this replacement battery because all of these battery are not equal. They may look the same but they are not equal in performance. However the price of these batteries allows you to buy several at a time. I am getting approximately 2 1/2 days of charge out the ones I purchased. I can't say for sure but I bet these are knock offs. Bottom line it's a better deal than paying over $40.00 for a BR50 at the dealers and not knowing whether it's going to do any better. The Razr is not a very good long term performance phone and these inexpensive batteries will do just fine for your needs.