The tube is 12" long it looks about 7/16" dia. alum or you can buy carbon fiber tubes PBG has them.
I know it's not easy to find these any more . I believe these are not made, Gator's house and shop was hit by a tornado some years ago and I am not sure if they are stll doing business.

If they are not in business any more I may just have to start making them in my cnc shop. Who know's I may even make the dies and have my friend that is in the injection molding business pop out a thousand of the mounting bracket made or of poly or plastic or what ever would be the strongest material for the part.

Then we would have plenty.