For the 80*120 concave tube, the "80*120" typically refers to the outer dimensions of the tube's cross-section, meaning the length and width of the cross-section are 120mm and 80mm respectively. However, in addition to the outer dimensions, the shape, depth, and wall thickness of the concave groove should also be considered, as these parameters can vary due to different manufacturers and specific application requirements. As for zinc steel channel tubes, there are various common sizes available.

Common sizes for zinc-aluminum alloy fence posts include 32*32, 35*35, and 40*40. Standard rectangular zinc-aluminum alloy channel pipe sizes typically include 20*30, 20*40, 30*40, 30*50, 30*60, 40*60, and 40*80. However, custom sizes for zinc-aluminum alloy channel pipes can also be produced according to customer requirements.