WOW you guys are a tough crowd
It maybe looks like phenolic tubing but an edge view shows what appears to be various layers of density. I've never seen phenolic tubing so I really don't know. I doubt it is sonotube. It works very well for me so I don't feel it is snake oil, floobydust or bait and switch. If a material is repurposed for something different from the original use does that mean it has no value? You know like Teflon in a non stick fry pan or Titanium in a golf club?
The cost is significantly less than a bunch of marbles between metal plates or springs in a cup. It works. I think it's clever.
Have any of you posters actually done anything to address the issue I'm talking about with their OB subs? Or do you just talk about it?
I love these emoticons and I mean no harm