I've had three of these DC9X power supplies. One lasted two years before it stopped working. I bought a replacement which broke after only a few uses - the plastic earth pin of the plug just snapped clean off! I returned the product and got a replacement. It now broke after around 3 months - the Earth pin just snapped off again!
The head of the plug is unrepairable, so I have the option of either buying another one or lots of batteries!