You need to be quite technical to install it you can get full instructions on YouTube it is slightly smaller than the original one but it still fits ok I'm works well I now get 3 to 4 days before I recharge on my watch instead of 2 to 3 hours
I had previously ordered replacement batteries for my watch from four other suppliers, and all of those were defective, having excess material at the corners which prevented them from fitting into the space in the watch. At last this one did fit.