1.25" od x 1/8" wall aluminum pipe.
No special material needed, just pipe!
6'6" long.
1/4" eye bolt with lock nut. The eye on the bolt is 1"od, installed 1/2" in from the end. Put one on each end.
Lay the boom flat and lay a pencil next to it and run it along the boom to make a line down the whole length. This way your holes will be in line with each other when you install the eye bolts.
No further reinforcement is necessary!

I put a bottle cap or a small block of wood or whatever, so the pencil slides better on whatever hard surface your using.

This works on just about any material that can lay flat. Round, flat, square, rectangular or triangular. Tubing or iron.