My original battery was dying, so this replacement battery was a much cheaper alternative to the cost of an original Lenovo replacement. It is quite a lot lighter than the original battery, which is due to the fact that the capacity of this battery is lower than the Lenovo original (the original claims 5.2AH and this one is 4.4AH), so it is not going to restore the battery life of my T61 to its length when new, but for the low price it is certainly worth it and I get 2+ hours out of it, which is all I was hoping for.