Sawdust catcher?

[dynabase]

I was looking at a SS pen making video and could not identify what he had hanging on the bottom of his SS.

https://www.youtube.com/watch?v=YtgpV8MJE0Q

My best guess is it is some sort of sawdust catcher. Anyone have any info on this? How well does it work?

[Gene Howe]

They look like those big gulp attachments for the DC hose. I tried one only and wasn't enamoured with it. Maybe two would be better.