I am looking for something like this to make my robot ideas as prototype. But I don't know it's name! Also if there are better options I will happy to know.
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What you're looking for is described as "Perforated", So a quick google for "Perforated Square Tubing Steel" produced: https://www.discountsteel.com/items/Galvanized_Steel_Perforated_Square_Tube.cfm
"80-20" is a brand name, and the product that @Donald Gibson was referring to can more generally be found called "T Slot Extrusion"