I'm selling a Datel Tool Battery (Padora Battery) for the Slim PSP, pics below. You can use it to downgrade your PSP and/or Unbrick your bricked PSP, its a great product, adult owned used only once, in excellant condition. It makes your PSP go into service mode so I don't know if you can use it as a regular PSP battery. Asking price is $50 including shipping if within the US. Otherwise we can negotiate.
The Package itself
The Battery in the boxes compartment
Comparison of the TOOL Battery to a Slim PSPs 3.6v 1200 mAh battery.
Intructions that come with the TOOL Battery
Reply to this thread or PM me if you are seriously interested in purchasing the battery.