Air Brake Pipe 20 N. B. with socket 20 N. [ Air Brake Pipe 20 N. B. with socket 20 N. B & Flange 20 N. B. for BOXNHL. Pipe as per WD- 08008- S- 11, Item- 9, Alt- 6 or latest, Stainless steel to ASTM- A312 schedule 40 S Gr. TP 304 ( ERW ) and socket & flange stainless steel to IS: 6911- 1992X04 Cr. 19 Ni 9 304 SI, as per WD- 08008- S- 11, Item- 14 & 15, Alt- 6 or latest and WD- 83062- S- 07, Alt- 6 or latest. ]