This would be the generic terms for product sold for industrial and commercial applications.

Without more text, I am sorry but I cannot pinpoint the exact configuration of the material.

The link below will show you some configurations that are most commonly sold and perhaps the specific one will pop out at you.
I do not clearly understand if you are talking about perforated steel tubing which can be square or rectangular or steel pipe which is round.
Another site which is awesome is #2. Check it out lots of pictures there too.