Had this a couple of months now and is happily sitting alongside my computer going well ......... you can hear very quiet clicking noise at times as it adjusts the power from over and under the set limit for NZ standards ........ which it is what it is designed and built for. I find hearing the quiet clicking noise quite comforting as it tells me it is doing the job it is supposed to and at times it stops clicking and l notice it straight away , silly really but ......... although it just means the power level is stable. A great little unit and very happy with the performance of it, much better than the other smaller older unit l had ....view more