Dummy Speaker Load

I’m not much of an electrical guy, and looking for a bit of advice. I’ve read about disconnecting your speakers while running a break-in or demagnetizing or such CD, and in their place putting some kind of resistor across the speaker leads. Just so you don’t have to worry about possibly loud volume for an hour while the CD runs.

So what exactly is this device? Can anyone point me to where I might find these, maybe even a source or part number? Sounds really basic lol but that's where I'm at. Any info much appreciated. Thanks.