For the replacement power supply. As long as the input voltage will cover 220-240V and the output voltage matches you'll be fine. My Thecus N5200 Pro NAS power supply failed around 4 years ago and I couldn't get a replacement. It has run ever since on a standard small desktop power supply that sticks out of the back and would fail a PAT test on first sight. As it's extremely well hidden and only ever physically accessed by me I'm not concerned. The NAS itself has to be around 15 years old now so the next thing that goes on it will result in a complete replacement of NAS and all 5 drives - that won't be cheap!