Don't recommend.
While they might work I have read on this forum that there was a knockoff brand being sold and where getting hot and catching fire.
There are plenty alternative chargers/ways to charge your system. If you decide to save a few bucks, find a known good seller that shows reviews for the product.
Some cheapo chinese chargers are so badly designed they could potentially damage hardware, although it's rare for that to happen.will it damage my n3dsxl?
Don't buy a mains/wall charger (3rd party). I usually buy 3DS usb chargers overseas and they are pretty good. (Still on my first one!)