I’d say (from my purely cinematic universe influenced opinion) strength goes:

From the length of your comment I get the feeling you feel strongly about Star Wars. But it was so long I didn’t bother to read it.

It’s actually slightly bigger. Some tables work off ball size, some use the magnetic gimcrack described above.

There used to be an extinguishing device that was a little glass ball that did something similar. The reason they aren't around anymore is because apparently the chemical inside was pretty toxic. Curious what this uses... Not curious enough to Google though.