what is on this duster?

[smilodon]

I just bought this duster, but something on it, when it retreat back to the tube, that little thing acts like a cap blocking the whole tube. I try to get it out by using tweezers, but that thing is really hard and slippery, and so deep in the tube to get it out.

anyone knows what that is?

 

[otrlynn]

Kind of hard to see from the picture, but you my possibly be seeing part of the worm itself, if it disappears when the worm pulls back into the tube.

 

[greenbean36191]

It's the operculum. As you've noticed, it's used to block the opening of the tube. Do not try to remove it. It is part of the worm.

 

[smilodon]

but why the other dusters don't have this operculum?

 

[WaterKeeper]

They don't live in as tough a neighborhood as the Operculum worm does.

There are many, many types of tube worms and their tubes and body structure differ.