Re: assuming you know what it is
I actually have a Brother labeller. Very useful for the assorted plugs that work my fish tank*. But it's too late for that to be used on the device leads now. And the next time I identify and use one I'll be in too much of a hurry to put a nice label on. At least, I'll be in a hurry by the time I've identified it and extracted it.
* pump, filter, front LED, rear LED, heater