Originally Posted by benjaminp
Doesnt your question answer itself? If they made a real difference, they would be more popular. I've never seen one before, cant imagine it would make as much difference as a ballast bag.
I was hoping to hear feedback from someone that had actually used one. Just because there aren't many around doesn't mean they don't function as intended. Maybe it's just one of those things that take a while to catch on
They seem to make sense, but I am no physics expert.