I needed a charger for when we take the e-reader but not laptop. I thought I could use an adaptor (Mini to Micro) so the charger I have for our PRS-350 could be used - but this didn't seem to work. So bought this. Works fine, charges up fairly quickly, and available at cheap price and prompt delivery. This plugs into the DC socket rather than the separate mini socket. (The PRS-350 has rationalised things and just has a micro socket for both computer connection and power charger)
It is a bit of a pain when we go away and take both our e-readers to have to take 2 chargers. But at least they work fine and were cheap.