Nothing is easier or faster than building with extrusion and we've added 20mm square aluminium extrusion and components to our catalog. This product is the extrusion itself. Made of aluminium, its exactly 20x20mm square and has slots on all four sides. You can use T-nuts that slide into the slots to connect plates, couplers, PCBs, cut-outs, etc.
We like the 20mm for being just large enough for sturdy DIY projects and robots, but not too clunky and heavy.
Just select the length you need from the options above. If we don't do the exact size you need, don't worry - each piece is easily cut down with a hacksaw or bandsaw.
Grab some T-nuts, screws and plates to build a frame, then finish off with end-caps.