Hi and thank you for your question. My name is ***** ***** I will be happy to assist you.
You can find a replacement battery by clicking here.
Also on the same page, you will find how to get to the battery to replace it. This is the best value because the purchased battery comes with the tools required to open the unit.
Please take a moment to rate my answer. If there is anything else I can help with, or if when you get the battery and you have trouble getting the unit open, please let me know!