The difference between pipe markings dn, de, φ, d, and d: dn refers to the nominal diameter of the pipe. Note: This is neither the outer diameter nor the inner diameter. It is the average of the outer diameter and the inner diameter, which is called the average inner diameter. For example: dn200~φ219×6 d generally refers to the inner diameter of the pipe. d concrete.
D9898, Blue Color, Shimmery Finish Paper, Hindu Cards.