I have an Nokkia cell phone that is ancient enough that people begin to titter when I take it out of my pocket in a public space. Works for me. It had the original battery, which finally, after many years, was not doing very well at holding a charge, although still useable. I had no idea that I could easily obtain a new battery for this phone until a friend suggested that I look on Amazon. The battery was available (BPS-2) and it didn't take long to locate it on the web site. Moreover, it was cheap. I ordered it (it came from one of Amazon's secondary suppliers) and received it promptly. It's installed, and my phone now holds a charge as if it were new. I should, however, warn people about this kind of replacement battery, which is built into the back of the phone case: the thickness may differ slightly from the original. If it's too thick, you won't be able to install it and should return it immediately for a refund. If it's too thin, you can probably use it. In my case, the replacement battery is very slightly too thin, and I had to put a piece of electrical tape on the inside of it so that the simcard, which lies directly underneath, does not wiggle vertically, lose contact, and shut down the phone. With the extra thickness provided by the tape, it works fine. I doubt that there is any way that suppliers can control for this.