Purchased battery for my 'dinosaur' Kyocera Marbl flip phone of 9yrs. A simple phone used basicly for incoming/outgoing calls no more, no less. Battery purchased about 8 wks ago & so far so good. Seems to work like the original battery that was purchased with the phone many moons ago. Battery takes maybe up to an hour to charge and since there are no apps to drain, it holds a pretty good charge for about 5 days or more. Which is pretty much what I required.