The new Tough Power XT models are not going to replace the originals but to offers some nice features that are not part of the older models. The XT series boast a single and powerful 12 volt rail. Yes we know this is not revolutionary but they have also added the neat ability to determine how much time after PC shuts down that the fan stop spinning. If that isn't enough the XT also tells you if anything is ailing it. If all this is not enough then you have to read the rest of the review to see what else the XT has to offer.