Instead of the sailboat mast material he uses for SWB singles, this time he is using industrial strength 6061-T6 aluminum handrail material about 2” by 5” by .125”wall . The raw piece was 10 feet long and weighed about 12.5 pounds.

It just looks like solid aluminum, because he did such a clean job of capping the end of the tube. Note the eccentric BB for adjusting connecting chain tension.