... steel decorative pipe a) Round tube and embossed tube : O. D. mm 9.5 , 12.7 , 15.9 , 17 , 18 , 19. 1 , 20 , 21 , 22 ... .2 , 23 , 25.4 , 28 , 31.8 , 33, 35, ... 10*10 , 12*12 , 15*15 , 18*18 , 19 * 19 , 20*10 , 20*20 , 22* 22 , 23* 11 , 23 *23 , 24* 12 , 24*24 , 25*13 , 25*25 ... ,100*100 , 120*60 , 150*100 , 150*150 c) Elliptical /oval pipe size (mm) 7.5*11.5, ...