[Tx Firefighter]

I used thick wall rectangular tubing. It was 1/8 or 1/4 inch thick, I don't remember now. I didn't see any need to box the ends, but I was doing it as a "governement project" back when I worked for the Post Office, so I had plenty of time to make them fancy.

I've seen lots of guys just use the tubing and leave them open front and rear.