Check this out.

Ok, so I see it's a fuse.

If the filament wire separates in the center, doesn't the copper powder still conduct?

Hay you got me. It's show and tell. I just happened across it. Interesting I thought.

Must be superb because has nano-copper. I hope the casing is airtight. Else the copper dust will oxidize and that wouldn’t be good. Assuming the copper dust (aka nano particles) does anything good in the first place.