Why am I so enthusiastic about AAAA batteries? Well, mostly because I don't have to think about them. Have these on reserve for my Surface Pen. The one it replaced seems to be going strong, having the rest on hand in such an accessible form factor and NOT having to scour through a CVS for such a specific purchase reminds me how fortunate I am to be alive in the age of Amazon. Do you need AAAA batteries? These are in fact functioning AAAA batteries.