Choosing square tube to be (60x40x3mm), or C shape steel (100x50x20x3mm) or rot-proof wood as the purline.
Họrọ square tube ịbụ (60x40x3mm), ma ọ bụ C udi nchara (100x50x20x3mm) ma ọ bụ osisi na-ere ure dị ka purline.